CodingMediumcod-g873

Subject Concurrency simulationLevel Mid–Senior~25 minCommon in Concurrency · Algorithms & data structures interviewsIndustries Software development, Technology

Question

A system has `n` threads `0..n-1`. A wait-for graph is given as a list of edges `[a, b]` meaning thread `a` is blocked waiting on a resource held by thread `b`. A deadlock exists if and only if the wait-for graph contains a directed cycle. Return `True` if there is a deadlock, otherwise `False`.

Implement

has_deadlock(n: int, wait_for: list[list]) → bool

Examples

in[3,[[0,1],[1,2],[2,0]]]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.

Learn the concepts

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.