quicksort

function
 partition(array, left, right, pivotIndex)
     pivotValue := array[pivotIndex]
     swap array[pivotIndex] and array[right]  // Move pivot to end

     storeIndex := left
     for
 i  from 
 left to
 right - 1 // left ≤ i < right

         if
 array[i] < pivotValue
             swap array[i] and array[storeIndex]
             storeIndex := storeIndex + 1
     swap array[storeIndex] and array[right]  // Move pivot to its final place

     return
 storeIndex

function
 quicksort(array, left, right)
     if
 right > left  // subarray of 0 or 1 elements already sorted

         select a pivotIndex in the range left ≤ pivotIndex ≤ right  // see Choice of pivot for possible choices

         pivotNewIndex := partition(array, left, right, pivotIndex)  // element at pivotNewIndex is now at its final position

         quicksort(array, left, pivotNewIndex - 1)  // recursively sort elements on the left of pivotNewIndex

         quicksort(array, pivotNewIndex + 1, right)  // recursively sort elements on the right of pivotNewIndex