create algorithms folder

Java/algorithms/MergeSort.java

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+public class MergeSort {
+
+    void merge(int arr[], int low, int mid, int up) {
+        int n1 = mid - low + 1;
+        int n2 = up - mid;
+
+        int Left[] = new int[n1];
+        int Right[] = new int[n2];
+
+        for (int i = 0; i < n1; ++i) {
+            Left[i] = arr[low + i];
+        }
+        for (int j = 0; j < n2; ++j) {
+            Right[j] = arr[mid + 1 + j];
+        }
+
+        int i = 0, j = 0;
+
+        int k = low;
+        while (i < n1 && j < n2) {
+            if (Left[i] <= Right[j]) {
+                arr[k] = Left[i];
+                i++;
+            } else {
+                arr[k] = Right[j];
+                j++;
+            }
+            k++;
+        }
+
+        while (i < n1) {
+            arr[k] = Left[i];
+            i++;
+            k++;
+        }
+
+        while (j < n2) {
+            arr[k] = Right[j];
+            j++;
+            k++;
+        }
+    }
+
+    void sort(int arr[], int low, int up) {
+        if (low < up) {
+
+            int mid = low + (up - low) / 2;
+
+            sort(arr, low, mid);
+            sort(arr, mid + 1, up);
+
+            merge(arr, low, mid, up);
+        }
+    }
+
+    static void printArray(int arr[]) {
+        int n = arr.length;
+        for (int i = 0; i < n; ++i) {
+            System.out.print(arr[i] + " ");
+        }
+        System.out.println();
+    }
+
+    public static void main(String args[]) {
+        int arr[] = {3, 5, 9, 6, 1, 4, 2, 8, 7};
+
+        System.out.println("Given Array");
+        printArray(arr);
+
+        MergeSort ob = new MergeSort();
+        ob.sort(arr, 0, arr.length - 1);
+
+        System.out.println("\nSorted array");
+        printArray(arr);
+    }
+}

Java/algorithms/bubbleSort.java

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+import java.util.Scanner;
+
+public class bubbleSort {
+
+    public static void main(String[] args) {
+        int num, i, j, temp;
+        Scanner input = new Scanner(System.in);
+        System.out.println("Enter the number of Soldiers:");
+        num = input.nextInt();
+        int array[] = new int[num];
+        System.out.println("Enter " + num + " soldiers heights in centrimeters(cm): ");
+ for (i = 0; i < num; i++) {
+            array[i] = input.nextInt();
+        }
+        for (i = 0; i < (num - 1); i++) {
+            for (j = 0; j < num - 1 - i; j++) {
+                if (array[j + 1] < array[j]) {
+                    temp = array[j];
+                    array[j] = array[j + 1];
+                    array[j + 1] = temp;
+                }
+            }
+        }
+        System.out.println("Sorted list of soldiers heights:");
+        for (i = 0; i < num; i++) {
+            System.out.println(array[i]);
+        }
+    }
+}

Java/algorithms/insertionSort.java

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+import java.util.Arrays;
+
+public class insertionSort {
+
+    static void InsertionSort(int[] array) {
+        for (int i = 1; i < array.length; i++) {
+            int key = array[i];
+            int j = i - 1;
+            while (j >= 0 && key < array[j]) {
+                array[j + 1] = array[j];
+                --j;
+            }
+            array[j + 1] = key;
+        }
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {9, 4, 3, 1, 7, 2, 8, 6, 5};
+        InsertionSort(arr);
+        System.out.println("Sorted Array: " + Arrays.toString(arr));
+    }
+}