Compare Algorithms
Two algorithms are easiest to tell apart when you see them next to each other. Pick any two or three of the 121 visualizers and compare what they cost and what they are for.
Quick Sort
Merge Sort
O(n log n)O(n log n)O(log n)O(n)Efficient divide and conquer algorithm that partitions the array around a pivot, placing elements smaller than the pivot to its left.
Divide and conquer algorithm that splits the array into halves, recursively sorts each half, then merges them back in sorted order.
Complexities come from each algorithm's own page, so they match what the visualizer shows. The “lowest” highlight compares the headline bound only — it is not a verdict, since the cheaper bound often costs something else, like quick sort's worst case or merge sort's extra array. For the full table, see the complexity cheatsheet.