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

Dijkstra's shortest paths

Settle the closest unsettled node, then try to shorten the distances of its neighbours. Works when no weight is negative.

Precondition: Edge weights must be 0 or more.

Make one edge heavier so the shortest path changes. Predict the new distances before running it.

Step 1 of 19

empty

Set dist[0] = 0. Every other node starts at ∞.

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.

Dijkstra's shortest paths

Settle the closest unsettled node, then try to shorten the distances of its neighbours. Works when no weight is negative.

Precondition: Edge weights must be 0 or more.