Quicksort?

void QuickSort(int[] arr, int low, int high)

if (low < high)

Follow on:

int pi = Partition(arr, low, high);

QuickSort(arr, low, pi - 1);

QuickSort(arr, pi + 1, high);

int Partition(int[] arr, int low, int high)

int pivot = arr[high];

int i = low - 1;

for (int j = low; j < high; j++)

if (arr[j] < pivot)

i++;

(arr[i], arr[j]) = (arr[j], arr[i]);

(arr[i + 1], arr[high]) = (arr[high], arr[i + 1]);

return i + 1;

Explanation:

Choose last element as pivot, partition array so left < pivot < right, recursively sort

subarrays.