QuickSort is a Divide and Conquer stable and in-place algorithm. It picks an element as pivot and partitions the given array around the picked pivot. In this version, the last element is chosen as the pivot. The key process in quickSort is partition() which when given an array and an element x of array as pivot, puts x at its correct position in sorted array and put all smaller elements (smaller than x) before x, and put all greater elements (greater than x) after x. All this should be done in linear time.