[알고리즘_풀이] 백준 - 토마토 java

https://www.acmicpc.net/problem/7576

7576번: 토마토

import java.util.*;

public class Main {
	static int answer = 0;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int M = sc.nextInt(); // 가로, j
		int N = sc.nextInt(); // 세로, i
		
		Node[][] a = new Node[N][M];
		Queue<Node> queue = new LinkedList<>();
		
		for(int i=0; i<N; i++) {
			for(int j=0; j<M; j++) {
				int input = sc.nextInt();
				a[i][j] = new Node(i, j, input);
				if(input == 1) {
					queue.add(a[i][j]);
					a[i][j].level = 0;
				}
			}
		}
		
		bfs(a, queue, M, N);
		
		
		for(int i=0; i<N; i++) {
			for(int j=0; j<M; j++) {
				if(a[i][j].value == 0) {
					answer = -1;
					break;
				}
			}
		}
		
		System.out.println(answer);
	}
	
	static void bfs(Node[][] a, Queue<Node> queue, int M, int N) {
		int[] di = {-1, 0, 1, 0};
		int[] dj = {0, 1, 0, -1};
		
		while(!queue.isEmpty()) {
			Node out = queue.remove();
			for(int k=0; k<4; k++) {
				int i = di[k] + out.yi;
				int j = dj[k] + out.xj;
				
				if(i<0 || i>=N || j<0 || j>=M) continue;
				
				if(a[i][j].value == 0) {
					queue.add(a[i][j]);
					a[i][j].level = out.level+1;
					a[i][j].value = out.level+1;
					answer = out.level+1;
				}
			}
		}
	}
	
	static class Node {
		int yi;
		int xj;
		int value;
		int level;
		
		Node(int yi, int xj, int value) {
			this.yi = yi;
			this.xj = xj;
			this.value = value;
			this.level = 0;
		}
	}

}

bfs