What Stays Warm

A medium Python interview practice problem on DataDriven. Write and execute real python code with instant grading.

Domain

Python

Difficulty

medium

Seniority

L3

Problem

An edge cache keeps only the `capacity` most recently requested keys live at once. Replay the request log in `ops`: an `['access', key]` entry marks that key as the most recently used, adding it when it is new and dropping the least recently used key whenever a new arrival would push the window past `capacity`; an `['snapshot']` entry records the keys held at that moment, most recently used first. Return one list per `['snapshot']` in order, and an empty list overall when the log holds no snapshots.

Summary

Memory is small and the stream never stops. Keep only what was just asked for, in the order it was asked.

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