Sorting Algorithms

Arrange data in order — and why the choice of algorithm matters.

Easy

Algorithm	Best	Average	Worst	Stable	Extra memory
Bubble	$n$	$n^2$	$n^2$	yes	$O(1)$
Insertion	$n$	$n^2$	$n^2$	yes	$O(1)$
Merge	$n\log n$	$n\log n$	$n\log n$	yes	$O(n)$
Quick	$n\log n$	$n\log n$	$n^2$	no	$O(\log n)$
Heap	$n\log n$	$n\log n$	$n\log n$	no	$O(1)$

A stable sort keeps equal items in their original order. Real libraries use hybrids like Timsort (Python, Java objects) and introsort (C++).

Sub-topics (3)

Bubble Sort

Repeatedly swap adjacent out-of-order elements until the list is sorted.

Beginner♥ 0🔖 0💬 0

Merge Sort

Divide the list in half, sort each half, then merge — always O(n log n).

Intermediate♥ 0🔖 0💬 0

Quick Sort

Pick a pivot, partition smaller and larger elements around it, and recurse.

Intermediate♥ 0🔖 0💬 0

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Sub-topics (3)

Bubble Sort

Merge Sort

Quick Sort

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