In-Memory Key-Value Store with Snapshot and Restore

Problem: In-Memory KV Store with Snapshot and Restore Implement an in-memory key-value store KVStore where both keys and values are strings. Support: put(key, value): Insert or overwrite a value. get(key): Return the value for key, or None if the key does not exist. delete(key): Remove a key. Deleting a missing key must be a no-op. snapshot(): Return a persistable serialized string representing the current store state. restore(data): Restore the store from a string previously produced by snapshot(). The current state must be completely replaced. Requirements: Snapshot output must be deterministic: identical store states produce identical strings. Keys and values may contain arbitrary characters, including delimiters, newlines, and Unicode. Do not use an unescaped delimiter-based format. After restore(snapshot()), every original key-value pair must be recovered correctly. Explain time and space complexity. Example put("a", "1") put("x:y", "hello\nworld") s = snapshot() delete("a") put("new", "value") restore(s) get("a") -> "1" get("x:y") -> "hello\nworld" get("new") -> None Constraints At most 10^5 operations. Each key or value has length at most 10^4. Total key/value data fits in memory. Example Input put("a", "1"); put("b", "2"); snapshot(); restore(snapshot); get("a"); get("b") Output "1"\n"2"