Your question is Concurrency-Safe Key-Value Store. 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).
How would you design a concurrency-safe key-value store?
Focus on correctness under concurrent access, durability, and high throughput. Clarify the consistency model, locking or versioning strategy, and how you would handle contention, replication, and failure recovery.