Your question is LRU Cache Design. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Design a cache system and implement it, using an LRU eviction strategy.
Define a clear cache interface, including lookup, insertion, update, and eviction behavior. Explain how the design achieves constant-time operations, handles updates and misses, and what additional decisions would be needed for concurrency, expiration, persistence, or distributed deployment.