Implement a Versioned Key-Value File Store
Company: Persona
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: hard
Interview Round: Take-home Project
Implement an in-memory file store that supports progressive requirements.
Operations include `set(key, value)`, `get(key)`, `delete(key)`, `scan()`, `scan_prefix(prefix)`, timestamped gets, and `set_ttl(key, value, timestamp, ttl)`. Expired keys must not be returned.
Implement:
```python
def process_file_store_operations(operations: list[list]) -> list:
pass
```
Return booleans for deletes, strings for gets, and lists of `key=value` strings for scans.
Quick Answer: Practice a Persona coding interview problem focused on implement a versioned key-value file store. The prompt emphasizes edge cases, clean implementation, and verifiable test behavior without revealing the solution.
Process file-store operations including set, get, delete, scan, prefix scan, timestamps, and TTL expiration.
Examples
Input: ([["set","a","1"],["get","a"]],)
Expected Output: ["1"]
Explanation: Basic set/get.
Input: ([["get","missing"]],)
Expected Output: [""]
Explanation: Missing key.