# What is the best and worst case of Quick Sort?

## What is the best and worst case of Quick Sort?

Most practical implementations of Quick Sort use randomized version. The randomized version has expected time complexity of O(nLogn). The worst case is possible in randomized version also, but worst case doesn’t occur for a particular pattern (like sorted array) and randomized Quick Sort works well in practice.

What is worst case scenario of Quick Sort?

When Does the Worst Case of Quicksort Occur? elements. Similarly, when the given input array is sorted reversely and we choose the rightmost element as the pivot element, the worst case occurs. Again, in this case, the pivot elements will split the input array into two unbalanced arrays.

Why does the worst case for Quick Sort occurs?

In early versions of Quick Sort where leftmost (or rightmost) element is chosen as pivot, the worst occurs in following cases. 1) Array is already sorted in same order. 2) Array is already sorted in reverse order.

### What is best case complexity of Quick Sort?

n*log(n)
Quicksort/Best complexity

What is the best case of quick sort give example?

2 Answers. A condition for the best case for Quicksort is that the pivot always goes right smack in the middle (except perhaps in the very last stages), so much is definitely correct.

What is the best case of merge sort?

Merge sort/Best complexity

## Why is quicksort better than mergesort?

Quicksort usually is better than mergesort for two reasons: Quicksort has better locality of reference than mergesort, which means that the accesses performed in quicksort are usually faster than the corresponding accesses in mergesort.

What is the worst case time complexity of quicksort?

The worst case time complexity of a typical implementation of QuickSort is O(n 2). The worst case occurs when the picked pivot is always an extreme (smallest or largest) element.

What is quick sort method?

Quick sort is a highly efficient sorting algorithm and is based on partitioning of array of data into smaller arrays.

### How does quick sort work?

First find the “pivot” element in the array.

• Start the left pointer at first element of the array.
• Start the right pointer at last element of the array.
• then move the left pointer to the right (add 1 to the left index).
• 