Merge sort code added

Author: me-shaon

Sorting/Merge Sort/merge-sort.js

@@ -0,0 +1,58 @@
+// Merge Sort Implementation
+function mergeSort(arr){
+    var len = arr.length;
+
+    if(len === 1) return arr;
+
+    var mid = Math.floor(len/2);
+    var left = arr.slice(0, mid);
+    var right = arr.slice(mid, len);
+
+    return merge(mergeSort(left), mergeSort(right));
+}
+
+function merge(left, right){
+    var result = [];
+    var leftCount = 0, rightCount = 0;
+
+    while(leftCount < left.length && rightCount < right.length){
+        if(left[leftCount] < right[rightCount])
+            result.push(left[leftCount++]);
+        else
+            result.push(right[rightCount++]);
+    }
+
+    while(leftCount < left.length){
+        result.push(left[leftCount++]);
+    }
+
+    while(rightCount < right.length){
+        result.push(right[rightCount++]);
+    }
+
+    return result;
+}
+
+
+/******************* Testing Merge sort algorithm *********************/
+
+/**
+ * Returns a random integer between min (inclusive) and max (inclusive)
+ * Using Math.round() will give you a non-uniform distribution!
+ */
+function getRandomInt(min, max) {
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+var arr = [];
+
+for(var i=0;i<10;i++){ //initialize a random integer unsorted array
+    arr.push(getRandomInt(1, 100));
+}
+
+console.log("Unsorted array: ");
+console.log(arr); //printing unsorted array
+
+arr = mergeSort(arr);
+console.log("Sorted array: ");
+console.log(arr); //printing sorted array