Thread-Safe LRU Cache With TTL | Dataford Interview Questions

Implement a thread-safe, memory-efficient LRU cache that supports time-based key expiration.

Implement lru_cache_operations(capacity, operations). Each operation is either ['put', key, value, ttl, now] or ['get', key, now]. A key expires when now >= insertion_time + ttl; expired keys behave as misses. Return values from get operations in order. Assume operation timestamps are nondecreasing, keys are strings, and capacity >= 1.

Constraints

1 <= capacity <= 10^4
1 <= operations.length <= 5000
Each operation is either ['put', key, value, ttl, now] or ['get', key, now]
Keys are strings
Values are JSON-compatible values
0 <= ttl <= 10^9
Operation timestamps are nondecreasing
All timestamps and TTLs are integers

Function Signature

def lru_cache_operations(capacity, operations):

Your question is Thread-Safe LRU Cache With TTL. Start with the requirements in the Question tab.

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Problem

Implement a thread-safe, memory-efficient LRU cache that supports time-based key expiration.

Constraints

1 <= capacity <= 10^4
1 <= operations.length <= 5000
Each operation is either ['put', key, value, ttl, now] or ['get', key, now]
Keys are strings
Values are JSON-compatible values
0 <= ttl <= 10^9
Operation timestamps are nondecreasing
All timestamps and TTLs are integers

Function Signature

def lru_cache_operations(capacity, operations):

Your question is Thread-Safe LRU Cache With TTL. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.