If the pivot used by quicksort is always the first element of an input array, the worst possible performance occurs when the input array is sorted.

Question

Quizplus · Accepted Answer

When the pivot is always the first element, and the array is already sorted, each partition step divides the array into two parts: one empty and the other containing all the remaining elements, leading to O(n^2) time complexity.

If the Pivot Used by Quicksort Is Always the First