Section 1Understand Problem
Section 01
Understand the problem
Restate the problem precisely. Interviewers reward candidates who pause, define the contract, and name the guarantees before coding.
Problem statement
You are given a network of `n` nodes, labeled from `1` to `n`. You are also given `times`, a list of travel times as directed edges `times[i] = [uᵢ, vᵢ, wᵢ]`, where `uᵢ` is the source node, `vᵢ` is the target node, and `wᵢ` is the time it takes for a signal to travel from source to target. We will send a signal from a given node `k`. Return the time it takes for all the `n` nodes to receive the signal. If it is impossible for all the `n` nodes to receive the signal, return `-1`.
Example
times = [[2,1,1],[2,3,1],[3,4,1]], n = 4, k = 2 → 2
Constraints
1 ≤ k ≤ n ≤ 100 · 1 ≤ times.length ≤ 6000 · 0 ≤ wᵢ ≤ 100
Audio recording unsupported on this browser.
WPM—Fillers0Pace—Thinking0%
Explain the problem in your own words
0 words0 chars
AI Review
Write your thinking above first.
Once you've drafted a response, click Submit for AI review and a senior engineer will critique your reasoning.
Ready to submit Section 1?
The reviewer will check whether you stated inputs, output, guarantees, and any assumption you flagged.
Write at least a couple of sentences explaining the problem before submitting.