TL;DR — Real-Time Leaderboard

Design a real-time leaderboard system that ranks millions of players by score and returns any player's rank in under 10ms. The system must handle score updates from concurrent game matches, support multiple leaderboard types (all-time, weekly, daily), and provide paginated views of the top-N players as well as a player's neighborhood (players ranked above and below them). Key features: Update player score (increment or set absolute value). Get top-N players with rank, name, and score (paginated).