Design an In-Memory KV Store with a Hit Counter

Design an in-memory Key-Value store that also maintains a hit counter. Requirements: Support basic operations: put(key, value): insert/overwrite get(key): read; if the key exists, increment that key's hit counter delete(key): remove the key Support querying the hit counter: hits(key): return how many successful get hits this key has had (define behavior if key does not exist) State complexity goals (e.g., average O(1) per operation). (Optional) Discuss concurrency/atomicity approaches (locks, RW locks, sharding, atomics). Suggested scale: up to 1e6 keys. Provide at least 5 test cases covering: basic put/get overwrite behavior after delete missing get correctness of hit counters Example Input put(a,1); get(a); hits(a) Output get(a)=1; hits(a)=1