Competitive Programming Helper (CPH)
Fetch a LeetCode problem's sample test cases and run them against your solution — without leaving VS Code.
Paste a problem URL, get a ready-to-fill C++ or Python solution file with the test cases already wired up, write your solution, and run it right from the editor.
Features
- Fetch test cases directly from a LeetCode URL — no browser extension required. Pulls the problem's function signature and sample inputs/outputs straight from LeetCode.
- Auto-generated solution templates for C++ and Python, matching LeetCode's own
class Solution format.
- LinkedList and Binary Tree support —
ListNode/TreeNode arguments and return values are automatically built from and serialized back to LeetCode's array notation (e.g. [1,2,3,4,5], [3,9,20,null,null,15,7]), so list/tree problems work out of the box.
- Run from the editor — a "▶ Run Test Cases" button (CodeLens) appears right above your
class Solution, or run from the webview panel.
- Manual test cases — add your own input/output pairs alongside the fetched ones, directly in the webview.
- Recently fetched problems — a sidebar view (Explorer → "Test Cases Explorer") lists problems you've fetched, one click to reopen.
- Each problem gets its own folder, so fetching a new one never overwrites a solution you're still working on.
Requirements
- C++ solutions require
g++ on your PATH (e.g. via MSYS2 on Windows, or Xcode Command Line Tools / build-essential elsewhere).
- Python solutions require
python on your PATH.
How to use
- Open the Command Palette (
Ctrl+Shift+P / Cmd+Shift+P) and run CPH: Open LeetCode Test Cases Webview.
- Paste a LeetCode problem URL (e.g.
https://leetcode.com/problems/two-sum/), pick C++ or Python, and click Fetch Test Cases.
- The generated solution file opens automatically. Write your solution in the
class Solution body.
- Click the ▶ Run Test Cases CodeLens above
class Solution (or the webview's Run Test Cases button) to see pass/fail results.
- Optionally add your own test cases via the webview's "Add a test case manually" box before running.
Extension Settings
This extension contributes the following setting:
competitiveProgrammingHelper.executionTimeoutMs: Maximum time (in milliseconds) a compiled/interpreted solution may run before being killed as timed out. Default: 5000.
Known Issues
Node* (random-pointer list) and N-ary Node problems aren't deserialized automatically — these fall back to a best-effort call that likely won't compile.- Only C++ and Python are supported.
- Fetched problems are stored under the extension's own install directory, so a Marketplace update to a new version clears your previously fetched problem history (your own solution code is unaffected unless you moved it elsewhere).
Release Notes
See CHANGELOG.md for full release notes.
0.1.0
Correctness fixes to test case parsing and C++ code generation, added LinkedList/TreeNode support, a "Run Test Cases" CodeLens, an execution timeout setting, manual test case entry, and a working "recently fetched problems" sidebar.
Enjoy!
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