Algorithm laboratory

Watch every stepthe algorithm takes

18 topics, each with its own source beside it. Step forward, step back, and watch the data move.

Browse the topics

Algorithm factory

Now. Awaiting start

Comparisons00

Swaps00

Pass0/6

Operationstandby

Pick the structure, then watch it work

Every topic opens with the data on one side and the source on the other. Choose a family to narrow the list.

Foundations

Sequential storage. The shapes the rest of the syllabus is built from.

Arrays6 techniquesMaster the fundamentals of memory layout and pointer manipulation.Sliding Window, Prefix Sum, Kadane, Two Pointers, Subarray Sum, Dutch Flag String6 techniquesUncover hidden patterns in text using advanced string matching algorithms.KMP, Rabin-Karp, Z-Algorithm, Trie, Suffix Array, LCS Sorting6 techniquesVisualize the divide and conquer strategies that power modern databases.Merge, Quick, Heap, Counting, Radix, Bucket

Structures

Linked, nested and branching. Each one draws its own shape on the canvas.

Stack6 techniquesPush and pop your way through expression parsing and history management.LIFO, Monotonic, Valid Parens, Next Greater, Min Stack, Histogram Queue6 techniquesManage scheduling and buffering tasks with first-in-first-out logic.FIFO, Priority, Deque, Sliding Max, BFS, Circular LinkedList6 techniquesWire and re-wire nodes dynamically to understand pointer logic.Singly, Doubly, Cycle, Reverse, Merge, Fast-Slow Hashing6 techniquesLearn how constant time lookups work under the hood.Maps, Sets, Collision, Two Sum, Group Anagrams, Subarray Sum Heaps6 techniquesEfficiently manage priority data for scheduling and graph algorithms.Min-Heap, Max-Heap, Insert, Heapify, Heap Sort, Top K Trees6 techniquesNavigate hierarchical data structures with recursive elegance.BST, AVL, Inorder, Preorder, Postorder, Level Order Tries6 techniquesOptimize dictionary searches and prefix matching.Prefix Tree, Autocomplete, Insert, Search, StartsWith, Delete Graphs6 techniquesModel real-world connections and find the shortest paths.BFS, DFS, Dijkstra, Shortest Path, Topo Sort, Cycle

Techniques

Ways of walking a sequence without going back over it.

Two Pointers6 techniquesTraverse data from multiple directions to reduce time complexity.Collision, Parallel, Sort Colors, Container, Remove Duplicates, Triplet Sliding Window6 techniquesEfficiently process subarrays without re-computing.Fixed, Dynamic, Max Sum, Min Size, Longest Substring, Anagrams Bit Manipulation7 techniquesOperate directly on binary data for extreme performance.AND, OR, XOR, Shifts, Masks, Power of Two, Subset Bits

Strategies

Frameworks for picking an approach before writing a line of code.

Recursion6 techniquesThe art of solving a problem by solving smaller instances of itself.Base Case, Call Stack, Divide-Conquer, Backtrack, Memo, Tree Backtracking6 techniquesExplore all potential solutions by building candidates incrementally.N-Queens, Sudoku, Subsets, Permutations, Combination Sum, Maze Greedy6 techniquesMake locally optimal choices to find a global optimum.Activity Selection, Huffman, Interval, Job Sequencing, Knapsack, Platforms Dynamic Programming6 techniquesBreak down complex problems into overlapping subproblems.Memoization, Tabulation, Fibonacci, Knapsack, LCS, Coin Change

The same four parts in every one

Only the algorithm changes between topics. Learn the layout once and all eighteen are the same page with different code in it.

Every visualizer on this page is these four panels and nothing else. There is no fifth view to hunt for, and no control that moves between one topic and the next.

Canvas: The structure itself, drawn live. Bars, nodes and edges all move as the step advances.
Source: The real implementation, not a paraphrase. The line about to execute is the only bright one.
Controls: Step forward, step back, autoplay, change the speed, feed it new input.
Complexity: Time and space recomputed at each step, rather than quoted once at the end.

If you are starting out, open these first

The index above is grouped by family, not by difficulty. This is the order that makes the rest easier to read.

01
Sorting
Comparisons, swaps and passes are impossible to hold in your head and obvious to watch.
Start here
02
Arrays
Pointers, bounds and swaps. The vocabulary every later technique is written in.
03
Two pointers
The pattern most interview answers rest on. Worth seeing move before memorising it.

Then find out whether you can pick one unaided

The visualizer shows how an algorithm moves. The problem set is where you find out whether you would have reached for the same one.

Start learning

Free forever
No card required
Proof on your profile