Cache with TTL | Dataford Interview Questions

Implement a cache handling system, including defining and managing TTL (time-to-live) expiration, checking elapsed time, and determining when items should be deleted.

Asked in the Onsite Coding Round stage. Write code for cache handling and deal with TTL logic under tight time constraints.

I/O Contract

Implement run_cache(operations). Each operation is a dictionary with op and a logical time. set also has key, value, and nonnegative ttl; get and delete have key; cleanup has only time. Return one result for each get, delete, or cleanup, in operation order. An expired or missing get returns None; delete returns a Boolean; cleanup returns expired keys in sorted order. An entry expires when time >= insertion_time + ttl.

Constraints

1 <= operations.length <= 10^4
Operation timestamps are nondecreasing
Keys are nonempty strings
Values are JSON-compatible values
0 <= ttl <= 10^9
Each operation has a valid operation type and required fields

Function Signature

def run_cache(operations):

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