The Heat of the Map

A hard Data Modeling interview practice problem on DataDriven. Write and execute real data modeling code with instant grading.

Domain

Data Modeling

Difficulty

hard

Seniority

senior

Problem

Grab's dispatch team runs a live map showing, for every geohash cell in a city, a surge multiplier driven by how far open requests outrun available drivers and a congestion score comparing observed speed to the road's free-flow speed, refreshed each minute. The schema backs both the always-on map, which needs only the current value in each cell, and analysts who replay how surge built up across a city over the past week. The cells nest, so a coarse cell's surge has to reconcile against the finer cells inside it and up to the one city each cell sits in, and you cannot get there by averaging one cell's ratio with another's.

Practice This Problem

Solve this Data Modeling problem with real code execution. DataDriven runs your solution and grades it automatically.