AI-powered coding practice
Solve AI-generated algorithm challenges by topic and difficulty — code in your browser with instant feedback. No signup to start.
144
problems
100%
free
No
signup
Custom problem
Pick a topic and difficulty — AI builds a fresh challenge just for you.
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Dedicated SQL trackNew
50 problems on real HR & e-commerce schemas — joins, subqueries, aggregation, and window functions.
FAQ
Yes. You can browse and solve our library of AI-generated algorithm problems for free, with no signup required to start. Generating brand-new custom problems on demand is a Plus feature.
Problems are generated by AI, so the catalogue keeps growing and you can create a fresh problem tailored to a specific topic or difficulty whenever you want. Each problem comes with worked examples, an in-browser code editor, and instant feedback.
Arrays, strings, hash maps, stacks, queues, linked lists, trees, graphs, heaps, two pointers, binary search, dynamic programming, backtracking, sorting, and math — plus general mixed problems.
Easy problems focus on a single core idea (~15 minutes). Medium problems combine concepts and edge cases (~25 minutes). Hard problems require non-obvious insight or optimal complexity (~40 minutes).
Yes. When signed in, solved and attempted problems are marked in the list and you can filter by status to focus on what you have not finished yet.