Class Solution


  • public class Solution
    extends Object
    1129 - Shortest Path with Alternating Colors.

    Medium

    You are given an integer n, the number of nodes in a directed graph where the nodes are labeled from 0 to n - 1. Each edge is red or blue in this graph, and there could be self-edges and parallel edges.

    You are given two arrays redEdges and blueEdges where:

    • redEdges[i] = [ai, bi] indicates that there is a directed red edge from node ai to node bi in the graph, and
    • blueEdges[j] = [uj, vj] indicates that there is a directed blue edge from node uj to node vj in the graph.

    Return an array answer of length n, where each answer[x] is the length of the shortest path from node 0 to node x such that the edge colors alternate along the path, or -1 if such a path does not exist.

    Example 1:

    Input: n = 3, redEdges = [[0,1],[1,2]], blueEdges = []

    Output: [0,1,-1]

    Example 2:

    Input: n = 3, redEdges = [[0,1]], blueEdges = [[2,1]]

    Output: [0,1,-1]

    Constraints:

    • 1 <= n <= 100
    • 0 <= redEdges.length, blueEdges.length <= 400
    • redEdges[i].length == blueEdges[j].length == 2
    • 0 <= ai, bi, uj, vj < n
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • shortestAlternatingPaths

        public int[] shortestAlternatingPaths​(int n,
                                              int[][] redEdges,
                                              int[][] blueEdges)