LeetVision

Dynamically visualize LeetCode executions, step-by-step.

**LeetVision — Step-by-Step Algorithm Visualizer for LeetCode & NeetCode** Stop guessing why your code fails. LeetVision watches your Python solution execute line-by-line, right inside a side panel next to your problem — no copy-pasting, no local setup, no leaving the tab. **What it does** LeetVision reads the code you've already written in the LeetCode or NeetCode editor and the visible example test cases on the page, runs it entirely inside your browser using a bundled Python runtime (Pyodide/WebAssembly), and animates exactly what your algorithm does at every step: which array elements your pointers are touching, what's getting inserted into a hashmap, how a linked list is being rewired, how a binary tree is being traversed. You can play, pause, and scrub through the execution like a video, and see immediately — visually — where a failing test case diverges from the expected output, down to the exact line and variable state. **Why it's different from just reading your code** Reading code tells you what should happen. Watching it execute tells you what actually happens. LeetVision closes that gap without requiring a debugger, a local Python install, or print statements scattered through your solution — everything runs client-side, in the panel, against the same examples already shown on the problem page. **Core features** - **Zero setup.** No backend, no account, no local environment — click the extension and go. - **Live tracing.** Every line of your submitted function is traced as it runs, capturing variable state at each step. - **Structure-aware animation.** Arrays, two-pointer patterns, hashmaps/sets, sliding windows, linked lists, and binary trees each get a visualization built for that shape, not a generic variable dump. - **Pass/fail against real examples.** Runs your code against the problem's own visible test cases and shows you where it agrees or disagrees with the expected output. - **Runtime error handling.** If your code crashes, LeetVision shows you exactly which line and what state triggered it — not just a stack trace. - **Play / pause / scrub controls.** Move through execution at your own pace, rewind to a step you want to look at again, or let it auto-play. - **Works with your existing workflow.** No changes to how you write or submit code — LeetVision reads what's already in the editor. **Supported today** Python solutions on NeetCode (primary support) and LeetCode. Support for arrays, hashmaps/sets, strings/sliding windows, linked lists, and binary trees. **Privacy** LeetVision runs entirely in your browser. Your code and test cases are read from the page and executed locally via the bundled Python runtime — nothing is sent to an external server. **Who it's for** Anyone learning algorithms and data structures for technical interviews who wants to actually see what their code is doing instead of just staring at a red X and a vague error message.