Code Room
CodingHardcod-g248
Subject Dijkstra variantsLevel Senior–Staff~40 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an undirected weighted graph with n nodes (0..n-1) and edges [u, v, w] with positive weights, return the length of the strictly second-shortest path distance from a source to a destination. Walks may revisit nodes and edges, so the second-shortest value may be strictly larger than the shortest even when only one simple route exists. Return -1 if no second distinct distance exists. Constraints: 1 <= n <= 500.

Implement
second_shortest_path(n: int, edges: list[list[int]], src: int, dst: int) → int
Examples
in[3,[[0,1,1],[1,2,1],[0,2,4]],0,2]out4
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.