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The CDN · D5

Place 3 edge caches to minimise total weighted latency.

Each user is served by the nearest cache; bigger dots = more traffic. Cover the users by distance — piling caches on the busiest city leaves everyone else far away.
Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.
Weighted latency
0
0 / 3 placed
tap the squares to place caches
About this puzzle

The CDN — practice the decision, scored against the optimum

What does the The CDN puzzle teach?

Cache placement is facility location — cover the users by weighted distance, don't pile caches on the busiest city.

Why do interviews ask about this?

What to cache at the edge is the CDN / performance interview: cache the objects with the best hit-rate per byte.

How is it scored?

The engine computes the provably-optimal answer for the exact instance you played (dynamic programming, shortest-path, or exhaustive search — never a heuristic) and scores your attempt as a percentage of it. No login needed to see your score.