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Grinding LeetCode in a bare editor means writing if __name__ == "__main__" prints, losing your test cases between attempts, and having nothing to show for a solved problem. leetcode-py generates a real software project per problem, tests, helpers, docs, and tooling included, so practice looks like the engineering you already do.

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Tests come with the problem

Every generated problem ships a parametrized pytest suite with 10+ cases, including edge cases, and a run_helper/assert_helper pair that keeps inputs readable in failure output. You never write test scaffolding; you only ever make red go green. Multiple solution approaches to the same problem? One test suite covers all of them via parametrized classes.

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Data structures you can see

TreeNode, ListNode, GraphNode, and DictTree convert between LeetCode’s array format and live objects, and render themselves as diagrams in Jupyter or clean ASCII in the terminal. Debugging a twisted tree traversal is much shorter when you can look at the tree. See Visualizations.

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300+ problems, ready to generate

The catalog covers the collections that matter (Grind 75, Blind 75, NeetCode 150, NeetCode 250, and Algo Master 75) as JSON templates that generate identical files on every machine. Browse everything in the Catalog, then lcpy gen -t <collection> and practice.

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Extensible by design

  • Template-driven: every problem comes from a JSON template plus a cookiecutter scaffold, so the tree stays consistent and reproducible. See Problem Creation.
  • LLM-assisted creation: the repo ships command specs that let Claude Code, Cursor, or Copilot add new problems and strengthen test suites following the house rules. See LLM-Assisted Problem Creation.
  • Production hygiene: type hints everywhere, loguru-powered test logs, 95%+ coverage, security scanning, and CI that verifies problems regenerate byte-identically from their templates.

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The loop

Generate, read the README, implement solution.py, run pytest, inspect in playground, next problem. Every problem, the same shape. That consistency is the feature: nothing between you and the algorithm except the algorithm.