Completed Quick Sort function, updated ReadMe.md

Author: C-Rodg

README.md

@@ -28,8 +28,8 @@ A collection of Javascript design patterns and common algorithms.
 - [ ] Find Identical Node
 - [x] Flatten Array
 - [x] Insertion Sort
-- [ ] Merge Sort
-- [ ] Quick Sort
+- [x] Merge Sort
+- [x] Quick Sort
 
 
 ## Contributors

algorithms/QuickSort.js

@@ -0,0 +1,33 @@
+function quickSort(arr, left, right) {
+	let len = arr.length,
+		pivot,
+		partitionIndex;
+
+	if(left < right) {
+		pivot = right;
+		partitionIndex = partition(arr, pivot, left, right);
+		quickSort(arr, left, partitionIndex - 1);
+		quickSort(arr, partitionIndex + 1, right);
+	}
+	return arr;
+}
+
+function partition(arr, pivot, left, right) {
+	let pivotValue = arr[pivot],
+		partitionIndex = left;
+
+	for(let i = left; i < right; i++) {
+		if(arr[i] < pivotValue) {
+			swap(arr, i, partitionIndex);
+			partitionIndex++;
+		}
+	}
+	swap(arr, right, partitionIndex);
+	return partitionIndex;
+}
+
+function swap(arr, i, j) {
+	let temp = arr[i];
+	arr[i] = arr[j];
+	arr[j] = temp;
+}