Implement a Map with Time Expiration

To implement a Map with Time-To-Live, I would combine a HashMap for fast key lookups with a Min-Heap to manage expiration order. First, we store each entry as an object containing the value, the insertion timestamp, and the TTL duration. When a 'put' operation occurs, we insert the key-value pair into the HashMap and push the expiration timestamp into the Min-Heap. For 'get' operations, we perform a lazy check: retrieve the value from the map, then verify if the current time exceeds the stored expiration timestamp. If expired, we remove it from both structures and return null. This ensures O(1) average time complexity for reads while maintaining efficient expiration handling. In a high-scale environment like Uber's, we might also consider a background daemon thread that periodically scans the heap's root to purge old entries, preventing the heap from growing indefinitely. We must ensure thread safety using fine-grained locking or concurrent hash maps to handle race conditions during simultaneous updates. This approach balances memory efficiency with low-latency access, crucial for real-time location tracking where stale data could lead to incorrect routing decisions.