Edge Cases and Robust Error Handling | Dataford Interview Questions

Verkada Command receives access events from multiple devices. Identify badge IDs that have at least max_denials valid denied attempts within any window_seconds interval.

Events may arrive out of order and can contain malformed records. Ignore records that are not dictionaries, have a blank or non-string badge_id, have a non-negative integer timestamp, or have an outcome other than "granted" or "denied". Only valid denied events contribute to the result. Invalid configuration must raise ValueError when window_seconds < 0 or max_denials < 1.

Formal Specification

Implement detect_repeated_denials(events, window_seconds, max_denials). events is a list of dictionaries with badge_id, timestamp, and outcome fields. Return a sorted list of badge IDs meeting the threshold. Two events belong to the same interval when their timestamp difference is at most window_seconds.

Constraints

0 <= len(events) <= 10^5
Valid timestamps are non-negative integers
0 <= window_seconds <= 10^9
max_denials >= 1
Malformed event records must be ignored
Invalid configuration must raise ValueError

Function Signature

def detect_repeated_denials(events, window_seconds, max_denials):

Your question is Edge Cases and Robust Error Handling. 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