Create QuickSort.js

Added Quick sort

SortingAlgorithms/QuickSort.js

@@ -0,0 +1,42 @@
+var items = [5,3,7,6,2,9];
+function swap(items, leftIndex, rightIndex){
+ var temp = items[leftIndex];
+ items[leftIndex] = items[rightIndex];
+ items[rightIndex] = temp;
+}
+function partition(items, left, right) {
+ var pivot = items[Math.floor((right + left) / 2)], //middle element
+ i = left, //left pointer
+ j = right; //right pointer
+ while (i <= j) {
+ while (items[i] < pivot) {
+ i++;
+ }
+ while (items[j] > pivot) {
+ j--;
+ }
+ if (i <= j) {
+ swap(items, i, j); //sawpping two elements
+ i++;
+ j--;
+ }
+ }
+ return i;
+}
+
+function quickSort(items, left, right) {
+ var index;
+ if (items.length > 1) {
+ index = partition(items, left, right); //index returned from partition
+ if (left < index - 1) { //more elements on the left side of the pivot
+ quickSort(items, left, index - 1);
+ }
+ if (index < right) { //more elements on the right side of the pivot
+ quickSort(items, index, right);
+ }
+ }
+ return items;
+}
+// first call to quick sort
+var sortedArray = quickSort(items, 0, items.length - 1);
+console.log(sortedArray); //prints [2,3,5,6,7,9]