Code RoomNetwork delay time
HardPrep Room Coding #1568

Network delay time

CodingAlgorithms & data structuresSenior–Staff~35 min

You are given a directed network of n nodes (labelled 1..n) and a list of travel times [u, v, w] meaning a signal from u reaches v after w time. A signal starts at node k. Return the time for all nodes to receive it, or -1 if some node is unreachable.

Implement
network_delay_time(times: list[list[int]], n: int, k: int) → int
Examples
in[[[2,1,1],[2,3,1],[3,4,1]],4,2]out2
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 35 min
InputExpectedGot
[[[2,1,1],[2,3,1],[3,4,1]],4,2]2not run yetsample