数据结构-图的遍历——BFS广度优先搜索-题解（Java代码）

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Scanner;
public class Main{
    static int[][] edges;
    static ArrayList<Integer> vertexList;
    boolean[] isVisited;
    public Main(int n){
       edges = new int[n][n];
       vertexList = new ArrayList<>(n);
       isVisited = new boolean[n];
    }
    public int getFirst(int index){
        for (int i = 0;i<vertexList.size();i++){
            if (edges[index][i]>0){
                return i;
            }
        }
        return -1;
    }
    public int getNext(int v1,int v2){
        for (int i = v2+1;i<vertexList.size();i++){
            if (edges[v1][i]>0){
                return i;
            }
        }
        return -1;
    }
    public void bfs(boolean[] isVisited,int index){
        System.out.print(vertexList.get(index)+" ");
        isVisited[index] = true;
        LinkedList queue = new LinkedList();
        queue.addLast(index);
        while(!queue.isEmpty()){
            int u = (int)queue.poll();
            int w = getFirst(u);
            while (w!=-1){
                if(!isVisited[w]){
                    System.out.print(vertexList.get(w)+" ");
                    queue.addLast(w);
                    isVisited[w] = true;
                }else {
                    w = getNext(u,w);
                }
            }
        }
    }
    public void bfs(){
        for (int i = 0;i<vertexList.size();i++){
            if(!isVisited[i]){
                bfs(isVisited,i);
            }
        }
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        Main m = new Main(n);
        for (int i = 0;i<n;i++){
            vertexList.add(i);
        }
        for (int i = 0;i<n;i++){
            for (int j = 0;j<n;j++){
                edges[i][j] = sc.nextInt();
            }
        }
        m.bfs();
    }
}