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

Climbing stairs

Count the ways to reach step n when each move climbs 1 or 2 steps. Each count is the sum of the two counts before it.

Compute the answer for n = 10 on paper using the recurrence. Then check it against the table.

Step 1 of 8

	0	1	2	3	4	5	6
ways	1	·	·	·	·	·	·

cell being filled cells it depends on

ways[0] = 1: there is one way to stand at the start.

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.

ways