What is the average case time complexity of quicksort?

What is the average case time complexity of quicksort?

The average case time complexity of quicksort is O(n log n). This occurs when the pivot divides the array into two roughly equal halves.

Why is it O(n log n)? Can you explain that?

Sure! In each recursive call, quicksort divides the array into two parts, and this division takes linear time, O(n). The depth of the recursion is log n, leading to the overall complexity of O(n log n).

How does it compare to other sorting algorithms?

Quicksort is generally faster than other O(n log n) algorithms like mergesort and heapsort due to lower constant factors and better cache performance.

Are there cases where quicksort performs poorly?

Yes, quicksort can perform poorly in the worst case, which is O(n^2), especially when the smallest or largest element is consistently chosen as the pivot.