Added the code of Merge Sort

MergeSort.java

@@ -0,0 +1,81 @@
+public class Mergesort {
+
+    public static void printarr(int arr[]) {
+
+        for (int i = 0; i < arr.length; i++) {
+            System.out.print(arr[i] + " ");
+        }
+
+        System.out.println();
+    }
+
+    // DIVIDE
+    public static void sort(int arr[], int si, int ei) {
+
+        // Base condition
+        if (si >= ei) {
+            return;
+        }
+
+        int mid = si + (ei - si) / 2;
+
+        // left side
+        sort(arr, si, mid);
+
+        // right side
+        sort(arr, mid + 1, ei);
+
+        // merging both the left and right side
+        merge(arr, si, ei, mid);
+    }
+
+    // CONQUER
+    // Function for merging the left and right array
+    public static void merge(int arr[], int si, int ei, int mid) {
+
+        // firstly, we will create a temporary array to merge the left and right side of
+        // the array
+        int temp[] = new int[ei - si + 1]; // size of the new array.
+
+        // Now we will make the iterator for both the parts
+        int i = si; // left part
+        int j = mid + 1; // right part
+        int k = 0; // temp array
+
+        while (i <= mid && j <= ei) {
+            if (arr[i] < arr[j]) {
+                temp[k] = arr[i];
+                i++;
+            } else {
+                temp[k] = arr[j];
+                j++;
+            }
+            k++;
+        }
+        while (i <= mid) {
+            temp[k] = arr[i];
+            i++;
+            k++;
+        }
+        while (j <= ei) {
+            temp[k] = arr[j];
+            j++;
+            k++;
+        }
+
+        // copy temporary to my original array
+        for (k = 0, i = si; k < temp.length; k++, i++) {
+            arr[i] = temp[k];
+        }
+    }
+
+    public static void main(String args[]) {
+
+        int arr[] = { 2, 5, 8, 4, 9, 3 };
+
+        sort(arr, 0, arr.length - 1); // Remember: ei is arr.length-1
+
+        printarr(arr);
+    }
+}
+// We use Depth first search to implement Merge sort