Code RoomDeadlock detection
MediumPrep Room Coding #1436

Deadlock detection

CodingConcurrencyAlgorithms & data structuresMid–Senior~25 min

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.

0:00 of about 25 min
InputExpectedGot
[3,[[0,1],[1,2],[2,0]]]truenot run yetsample