Part 3 · Module 25

Spatial indexing

Find what's near a point without scanning everything: geohashes and space-filling curves, quadtrees, and the cell systems (S2, H3) behind maps, ride-hailing and delivery apps.

Start

0 of 3 lessons21 min

25.1GeohashUp next7m
25.2Quadtrees, S2 and H37m
25.3Tracking moving objects7m
LabNearest five ridersFinish “Add a cache node without a stampede” first40m

Practice what this module teaches

Nearby Places Search HLDFind nearby places using spatial candidates, exact distance filtering and bounded queries.Intermediate45 min Ride Matching HLDMatch riders with nearby drivers while handling stale locations and acceptance races.Advanced55 min Geofenced Location Alert Platform

3day streak

Derive enter/exit alerts from ordered location observations with uncertainty and hysteresis.