Real-Time Fraud Cache Lookup | Dataford Interview Questions

Implement an efficient lookup mechanism for a real-time fraud detection cache. Store fraud decisions by key, return only unexpired entries, and evict the least recently used entry when capacity is exceeded. Implement fraud_cache_lookup(capacity, operations), where each operation is a dictionary: {"op": "put", "key": str, "value": str, "expires_at": int} or {"op": "get", "key": str, "at": int}. Return a list containing each GET result, using None for a miss or expired entry. Both GET and PUT operations should run in O(1) average time.

Constraints

1 <= capacity <= 10^4
1 <= operations.length <= 10^3
Keys are non-empty strings
Values are strings
Expiration and lookup times are integers
A GET is expired when at >= expires_at

Function Signature

def fraud_cache_lookup(capacity, operations):

Your question is Real-Time Fraud Cache Lookup. 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.

Problem

Constraints

1 <= capacity <= 10^4
1 <= operations.length <= 10^3
Keys are non-empty strings
Values are strings
Expiration and lookup times are integers
A GET is expired when at >= expires_at

Function Signature

def fraud_cache_lookup(capacity, operations):

Your question is Real-Time Fraud Cache Lookup. 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.