Code Room
CodingMediumcod-g708
Subject Dijkstra variantsLevel Mid–Senior~30 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

An undirected graph on n nodes (0..n-1) has weighted edges [u, v, w] with positive weights. Among all shortest (minimum total weight) paths from s to t, return the minimum number of edges (hops) used by any such shortest path. Return -1 if t is unreachable. Constraints: 1 <= n <= 10^4; 1 <= w <= 10^6.

Implement
min_hops_on_shortest(n: int, edges: list[list[int]], s: int, t: int) → int
Examples
in[4,[[0,1,1],[1,3,1],[0,2,1],[2,3,1],[0,3,2]],0,3]out1
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.