Algorithm visualizer

See every step, with your own input

Pick an algorithm, enter your own numbers or use a preset, then step through the run. The pseudocode and the explanation follow each step.

Arrays and searching

Sorting

Stacks, queues and Fenwick tree

Trees and tries

Graphs

Dynamic programming

Greedy and backtracking

Stack: push, pop, peek

Last in, first out. Push adds to the top, pop removes from the top, and peek reads the top without removing it.

Write an operation list that ends with an empty stack after several pushes. Does the stack's final state match your prediction?

Step 1 of 6

Stack (top on the right)empty

Start with an empty stack.

Speed

Labels under values name their role, such as lo, hi, mid, i, j, min, L and R. Faded items are already ruled out or already in place.