输入

  1. 5 5 #几个点 几条边
  2. 1 2 #具体边的连接
  3. 1 3
  4. 1 5
  5. 2 4
  6. 3 5
  1. import java.util.*;
  2. class Solution{
  3.     boolean[] f;
  4.     public void solve(int[][] graph, int N, int b){
  5.         f = new boolean[N + 1];
  6.         Queue<Integer> q = new LinkedList<>();
  7.         q.offer(b);
  8.         f[b] = true;
  9.         //res存储每一个节点
  10.         ArrayList<Integer> res = new ArrayList<>();
  11.         while(!q.isEmpty()){
  12.             int cur = q.poll();
  13.             // System.out.print(cur + " ");
  14.             res.add(cur);
  15.             for(int i = 0; i <= N; i++){
  16.                 if(graph[cur][i] == 1 && f[i] == false){
  17.                     q.offer(i);
  18.                     f[i] = true;
  19.                 }
  20.             }
  21.         }
  22.         for(int x : res){
  23.             System.out.print(x + " ");
  24.         }
  25.     }
  26. }
  27. public class Main {
  28.     public static void main(String[] args) {
  29.         Scanner cin = new Scanner(System.in);
  30.         int N = cin.nextInt();
  31.         int[][] graph = new int[N + 1][N + 1];
  32.         int M = cin.nextInt();
  33.         for(int i = 0; i <= N; i++){
  34.             for(int j = 0; j <= N; j++){
  35.                 if(i == j) graph[i][j] = 0;
  36.                 else graph[i][j] = Integer.MAX_VALUE;
  37.             }
  38.         }
  39.         for(int i = 0; i < M; i++){
  40.             int a = cin.nextInt();
  41.             int b = cin.nextInt();
  42.             graph[a][b] = 1;
  43.             graph[b][a] = 1;
  44.         }
  45.         new Solution().solve(graph, N, 1);
  46.     }
  47. }