Quicksort Pivot

Question

Sort the following array a using quicksort,

[6, 11, 4, 9, 8, 2, 5, 8, 13, 7]

The pivot should be chosen as the arithmetic mean of the first

Answer 1

Your pivot is 6. Your pivot is NOT the 6th element Now you can apply the following algorith.

function quicksort(array)
 var list less, greater
 if length(array) ≤ 1
     return array  // an array of zero or one elements is already sorted
 select and remove a pivot value pivot from array
 for each x in array
     if x ≤ pivot then append x to less
     else append x to greater
 return concatenate(quicksort(less), pivot, quicksort(greater))