Added merge sort

java/MergeSort.java

@@ -0,0 +1,56 @@
+class MergeSort {
+
+    public static void merge(int[] left_arr,int[] right_arr, int[] arr,int left_size, int right_size){
+
+        int i=0,l=0,r = 0;
+        //The while loops check the conditions for merging
+        while(l<left_size && r<right_size){
+
+            if(left_arr[l]<right_arr[r]){
+                arr[i++] = left_arr[l++];
+            }
+            else{
+                arr[i++] = right_arr[r++];
+            }
+        }
+        while(l<left_size){
+            arr[i++] = left_arr[l++];
+        }
+        while(r<right_size){
+            arr[i++] = right_arr[r++];
+        }
+    }
+
+    public static void mergeSort(int [] arr, int len){
+        if (len < 2){return;}
+
+        int mid = len / 2;
+        int [] left_arr = new int[mid];
+        int [] right_arr = new int[len-mid];
+
+        //Dividing array into two and copying into two separate arrays
+        int k = 0;
+        for(int i = 0;i<len;++i){
+            if(i<mid){
+                left_arr[i] = arr[i];
+            }
+            else{
+                right_arr[k] = arr[i];
+                k = k+1;
+            }
+        }
+        // Recursively calling the function to divide the subarrays further
+        mergeSort(left_arr,mid);
+        mergeSort(right_arr,len-mid);
+        // Calling the merge method on each subdivision
+        merge(left_arr,right_arr,arr,mid,len-mid);
+    }
+
+    public static void main( String args[] ) {
+        int [] array = {12,1,10,50,5,15,45};
+        mergeSort(array,array.length);
+        for(int i =0; i< array.length;++i){
+            System.out.print(array[i]+ " ");
+        }
+    }
+}