AlgoScope is a visual lab for data structures and algorithms. Pick a lesson, press play, and watch the algorithm run one step at a time, then predict what happens next before it does.

Every lesson is a simulation you control: play, pause, step forward and back, scrub the timeline, change the speed, and enter your own input to see how the algorithm handles it. Each step has a one-line explanation of what just happened and why.

See it run
Watch binary search narrow the range, merge sort split and merge, and a binary search tree change shape as you insert and delete keys. Every value, pointer and comparison is on screen.

Interact
Type your own array, choose your own target, insert your own keys. The animation is generated from your input, not played from a recording.

Predict
At key moments the lesson stops and asks what happens next. Answer, then watch. This is what turns watching into understanding.

Understand
Short explanations sit on the exact step that raised the question. There are no chapters to read first.

What is inside
331 interactive topics across 29 areas, from the first array to network flow.
Data structures: arrays, linked lists, stacks, queues, hash tables, binary search trees, AVL and red-black trees, heaps, tries, segment trees, Fenwick trees, disjoint sets.
Sorting and searching: every classic sort from bubble to radix, binary search and its variants, order statistics.
Graphs: BFS and DFS, Dijkstra, Bellman-Ford, Floyd-Warshall, Prim, Kruskal, topological sort, strongly connected components, bridges, max flow.
Techniques: dynamic programming, greedy, divide and conquer, backtracking, recursion, sliding window, two pointers, bit manipulation, string algorithms, number theory, computational geometry.
The 51 topics still in progress are listed in the app as coming soon, and every update fills more of them in.

Made for studying
- Works fully offline; everything is on your device.
- No account, no sign-in, no ads.
- Free for students.
- Phone and tablet layouts.
- Dark theme, reduced motion, screen-reader labels on every element, and colours chosen to stay readable with colour-blindness.
- Deterministic: the same input always produces the same steps, so a lesson can be repeated exactly.

Who it is for
Computer science students meeting data structures for the first time. Anyone preparing for a placement, an exam or a coding interview who wants to understand the algorithm rather than memorise the answer. Teachers who want a visualization that responds to the class's own examples.

Privacy
Anonymous usage analytics only, with an off switch in Settings. No personal data and no advertising ID. The full policy is linked on this page.

If a lesson could be clearer, tell us through the support link.