CodingMediumcod-g289

Subject Shortest pathLevel Mid–Senior~30 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given n cities (0..n-1) and a list of directed flights [from, to, price], find the cheapest total price to travel from src to dst using at most k intermediate stops (so at most k+1 flights). Return the cheapest price, or -1 if no route within the stop limit exists. Prices are non-negative integers.

Implement

cheapest_k_stops(n: int, flights: list[list[int]], src: int, dst: int, k: int) → int

Examples

in[4,[[0,1,100],[1,2,100],[2,3,100],[0,3,500]],0,3,1]out500

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.

Learn the concepts

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.