Bus Routes
Explore graph traversal techniques to solve the bus routes problem by finding the minimum number of buses required to travel between stations. Understand how to model routes as graphs and apply algorithms to optimize travel paths efficiently.
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Statement
You are given an array, routes, representing bus routes where routes[i] is a bus route that the bus repeats forever. Every route contains one or more stations. You have also been given the source station, src, and a destination station, dest. Return the minimum number of buses someone must take to travel from src to dest, or return -1 if there is no route.
Constraints:
-
routes.length -
routes[i].length -
routes[i][j] -
src,dest
Examples
Understand the problem
Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:
What is the output if the following input is given?
Bus routes = [[4, 2, 12], [3, 26], [1, 10], [4, 26, 6]]
src = 3
dest = 12
2
3
4
-1
Figure it out!
We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.
Try it yourself
Implement your solution in the following coding playground.
import java.util.*;class MinimumBuses {public static int minimumBuses(int[][] busRoutes, int src, int dest) {// Replace this placeholder return statement with your codereturn -1;}}