Cache of 3. On a full-cache miss, evict to keep total misses lowest.

Requests stream left to right. A miss with a full cache makes you evict one item. LRU is a guess — read ahead and evict the item used farthest in the future (that's Belady, the optimum).

Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.

Request stream

57757336613316333335527343

Cache · 3 slots

4 misses

miss on 6 — tap a slot to evict

The Cache — practice the decision, scored against the optimum

What does the The Cache puzzle teach?

LRU is a guess; Belady (evict the item used farthest in the future) is the provable optimum.

Why do interviews ask about this?

Cache eviction (Belady vs LRU) is a classic systems interview: why optimal eviction needs the future, and why LRU approximates it.

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.

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Practice0:00

The Cache · D3

Cache of 3. On a full-cache miss, evict to keep total misses lowest.

Requests stream left to right. A miss with a full cache makes you evict one item. LRU is a guess — read ahead and evict the item used farthest in the future (that's Belady, the optimum).

Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.

Request stream

57757336613316333335527343

Cache · 3 slots

4 misses

miss on 6 — tap a slot to evict