Quadtree
Domain: Data Structures
🎯 Motivation
A tree that recursively divides 2D space into four quadrants. Used in games, maps, and image compression for spatial queries.
📋 Concrete Example
A map of Hong Kong divided into 4 quadrants. If a quadrant has too many points, it subdivides into 4 smaller quadrants. Repeat until each quadrant has few points.
🔗 Analogy
A pizza cut into 4 slices. If a slice has too many toppings, cut that slice into 4 smaller slices. Keep cutting until each piece is manageable.