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Data Structures & Algorithms

26 interactive visuals

16 Beginner10 Intermediate1 Advanced

Concepts

6

Time ComplexityHow algorithms scale

Space ComplexityWatch memory grow — O(1), O(n), and O(n²) side by side

RecursionUnderstand recursion visually using factorial and Fibonacci

MemoizationCache results to avoid recomputing the same subproblem twice

IntermediateOpen

FibonacciWhy naive recursion is O(2ⁿ) — and how memoisation fixes it

Sliding WindowTurn O(n²) subarray problems into O(n) with a moving window

IntermediateOpen

Data Structures

6

ArraysO(1) random access, contiguous memory — the most fundamental data structure

Linked ListO(1) head operations, O(n) access — pointer-linked nodes in memory

Stack & QueueLIFO vs FIFO — two structures, two totally different orders

Hash TableO(1) average get, set, and delete — the backbone of fast lookups

HeapO(log n) insert and extract — the foundation of priority queues

IntermediateOpen

BST OperationsSearch, insert, and delete in O(log n) — with the in-order successor explained

IntermediateOpen

Sorting

9

Bubble SortRepeatedly swapping adjacent elements

Selection SortRepeatedly selects the smallest element

Insertion SortBuilds a sorted list one element at a time

Merge SortDivide, sort, and merge

Quick SortPick a pivot, partition, repeat — sorting at its fastest

IntermediateOpen

Shell SortInsertion sort with a shrinking gap — sort far-apart elements first

IntermediateOpen

Heap SortBuild a max-heap, then extract the largest element one by one

IntermediateOpen

Counting SortSort integers in O(n+k) — no comparisons, just counting

Radix SortSort by digits — no comparisons, just bucketing

IntermediateOpen

Searching

5

Binary SearchSearch by halving the range

Linear SearchFinds an element by checking one value at a time

Jump SearchO(√n) — jump forward in blocks, then scan back linearly

IntermediateOpen

Interpolation SearchO(log log n) on uniform data — smarter than binary by estimating position

String MatchingFind every pattern occurrence in text — naive O(n·m) vs KMP O(n+m)

IntermediateOpen