Built for algorithm learners

TRACE IT.
SOLVE IT.

TraceLab turns LeetCode solutions into synchronized, step-by-step visual traces of code, variables, pointers, and state.

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Semantic color language Local input replay Python, Java, C++ & JS

dungeon_game.py LIVE TRACE

05rows, cols = len(dungeon), len(dungeon[0])

06inf = float("inf")

07dp = [[inf] * (cols + 1) for _ in range(rows + 1)]

08dp[rows][cols - 1] = dp[rows - 1][cols] = 1

09for r in range(rows - 1, -1, -1):

10for c in range(cols - 1, -1, -1):

11need = min(dp[r+1][c], dp[r][c+1]) - dungeon[r][c]

12dp[r][c] = max(1, need)

13return dp[0][0]

Dungeon

-2-33-5-1011030-5

Min health DP

7526115116

Transition at (1, 1) min(right: 5, down: 1) − (−10) = 11 HP

How it works

Turn an algorithm into something you can see.

TraceLab solves the problem once, turns the execution into a teachable visual trace, and lets you experiment without paying for another model call.

01
Paste the problemAdd the prompt and choose your preferred programming language.
02
Generate the traceGet the optimal solution, complexity analysis, variables, and synchronized visualization.
03
Learn by changing itEdit the input and replay every decision locally, without calling the model again.

See the learning loop

One problem. Every decision visible.

See it in action 🎬

TRACE 12 / 18Dynamic Programming

How TraceLab helps

From confusion to clarity.

One focused learning loop. No black boxes.

See state, not slides

Watch pointers, links, tables, and invariants change on every meaningful line.

Code stays in sync

The active statement, local variables, and derived values move with the visualization.

One solve, endless inputs

Generate once, then replay custom inputs locally without another model call.

Start with the real product

See every decision for yourself.

Open the curated Two Sum trace instantly, then change the input and replay each step at your own pace.