package com.daxiong.arithmetic;

import java.io.*;
import java.util.*;

public class BFS {

    static int[][] data;
    static int vertex,depen,start,end;
    static int[] queue;
    static int[] visit;

    public static void main(String[] args) throws Exception{
        Scanner sc = new Scanner(new File("src/case/bfs.txt"));
        vertex = sc.nextInt();
        data = new int[(vertex+1)][(vertex + 1)];
        depen = sc.nextInt();
        for(int i =0;i < depen;i++){
            data[sc.nextInt()][sc.nextInt()] = 1;
        }
        sc.close();
        queue = new int[100];  // 队列
        visit = new int[100];
        start = 1;
        end = 0;
        queue[end++] = 8;
        visit[0] = 1;
        print();
        bfs(8,2,1);
        for(int i =0;i < 20;i++){
            System.out.println(queue[i] + " : " + visit[i]);
        }
    }

    static void bfs(int row,int step,int curStep){
        int temp = 0;
        int start_temp = 0;

        if(row > vertex){
            return;
        }
        if(start > end){
            return;
        }
        for(int i = 1;i <= vertex;i++){
            if(data[row][i] != 0){
                temp = end;
                queue[temp] = i; // 入队
                //System.out.println(i);
                visit[temp] = step;
                end++;
            }
        }
        start_temp = start;
        int col = queue[start_temp];  // 出队
        start++;
        if(visit[start_temp] <= curStep){
            bfs(col,step,visit[start_temp]);
        } else {
            bfs(col,step+1,visit[start_temp]);
        }
    }

    static void print(){
        for(int i = 1;i <= vertex;i++){
            for(int j =1;j <= vertex;j++){
                System.out.print(data[i][j] + " ");
            }
            System.out.println();
        }
        System.out.println();
    }
}