백준 7576번 토마토 JAVA

링크텍스트

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

public class Main{
	static int m,n;
	static int [] dx ={0,0,-1,1};
	static int [] dy ={1,-1,0,0};
	static int [][] arr;
	static Queue<int []> q = new LinkedList<>();
	static int count = 0;
	static int day = 0;

	public static void main(String[] args)throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());

		m = Integer.parseInt(st.nextToken());
		n = Integer.parseInt(st.nextToken());

		arr = new int[n][m];

		for(int i=0;i<n;i++){
		    st = new StringTokenizer(br.readLine());
			for(int j=0;j<m;j++){
				arr[i][j] = Integer.parseInt(st.nextToken());
				if(arr[i][j]==1){
					q.add(new int[] {i,j});
				}else if(arr[i][j]==0){
					count++;
				}
			} 
		}
		bfs();
	}

	public static void bfs(){
		while(count>0 && !q.isEmpty()){
                int size = q.size();
			for(int i=0;i<size;i++){
			    int [] point = q.poll();
			    int cx = point[0];
			    int cy = point[1];
			    
			    for(int j=0;j<4;j++){
			        int xx = cx + dx[j];
			        int yy = cy + dy[j];
			        
			        if(xx>=0 && xx<n && yy>=0 && yy<m && arr[xx][yy]==0){
			            q.add(new int[] {xx,yy});
			            arr[xx][yy]= 1;
			            count--;
			        }
			        
			    }
			}
			day++;
		}
		if(count==0){
		    System.out.println(day);
		}else
		    System.out.println(-1);
		
	}
}