Each one started as a question I couldn’t answer until I built it. None of these are toy implementations. They’re full systems, with the rough edges I had to learn to file down.
A chess engine in C++17, built from scratch. Started with array boards and minimax; ended with bitboards, alpha-beta pruning, Zobrist transposition tables, killer-move and history heuristics. Iteratively benchmarked on 100 Lichess mate-in-3 puzzles.
Head-to-head movie ranking with Elo. Dynamic K-factors by rating tier and comparison count, weighted pairing for competitive matchups, atomic vote transactions to prevent rating race conditions. TMDB integration for metadata.
Real-time collaborative music playlist app with priority-queue voting. Playlist order propagates to all clients via Socket.IO in ~80ms locally. Redis caching halved YouTube API quota usage; ACID-compliant concurrent vote handling validated with k6.