Algorithm Race

Which sorting algorithm wins?

Race 6 classic sorting algorithms head-to-head on identical data. Change the input type and watch the winner change. See exactly why algorithm choice matters for GCSE and A-Level CS.

Array Size

40 elements

Speed

Input Type

Algorithm	Best Case	Average Case	Worst Case	Space	Stable?
Bubble Sort	`O(n)`	`O(n²)`	`O(n²)`	`O(1)`	Yes
Insertion Sort	`O(n)`	`O(n²)`	`O(n²)`	`O(1)`	Yes
Selection Sort	`O(n²)`	`O(n²)`	`O(n²)`	`O(1)`	No
Merge Sort	`O(n log n)`	`O(n log n)`	`O(n log n)`	`O(n)`	Yes
Quicksort	`O(n log n)`	`O(n log n)`	`O(n²)`	`O(log n)`	No
Shell Sort	`O(n log n)`	`O(n log² n)`	`O(n²)`	`O(1)`	No