Code Room
CodingMediumcod-g677
Subject Concurrency simulationLevel Mid–Senior~35 minCommon in Concurrency · Algorithms & data structures interviewsIndustries Software development

Question

Detect deadlock from a resource wait-for graph. You are given a list of [holder, waiter] edges meaning the `waiter` thread is blocked waiting on a resource currently held by the `holder` thread. A deadlock exists iff this directed graph contains a cycle. Return True if any cycle exists, otherwise False. Thread identifiers are arbitrary hashable values (ints).

Implement
has_deadlock(edges: list[list[int]]) → bool
Examples
in[[[1,2],[2,3],[3,1]]]outtrue
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.