[백준 2178] 미로탐색_ 자바Java

1. 문제

https://www.acmicpc.net/problem/2178

2. 코드

import java.awt.Point;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class BOJ2178 {

	static int N, M;
	static int[][] grid;
	static int[] dx = { 0, 0, -1, 1 };
	static int[] dy = { -1, 1, 0, 0 };
	static boolean[][] isVisited;

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

		// input
		StringTokenizer st = new StringTokenizer(in.readLine(), " ");
		N = Integer.parseInt(st.nextToken());
		M = Integer.parseInt(st.nextToken());
		grid = new int[N][M];
		isVisited = new boolean[N][M];

		for (int i = 0; i < N; i++) {
			String row = in.readLine();
			for (int j = 0; j < M; j++) {
				grid[i][j] = row.charAt(j) - '0';
			}
		}

		// call the bfs()
		bfs(0, 0);

		System.out.println(grid[N - 1][M - 1]);
		in.close();

	}

	private static void bfs(int x, int y) {
		Queue<Point> queue = new LinkedList<Point>();

		queue.add(new Point(x, y));
		while (!queue.isEmpty()) {
			Point p = queue.poll();
			isVisited[x][y] = true;

			for (int i = 0; i < 4; i++) {
				int nx = p.x + dx[i];
				int ny = p.y + dy[i];

				if (isValid(nx, ny) && grid[nx][ny] == 1 && !isVisited[nx][ny]) {
					queue.add(new Point(nx, ny));
					isVisited[nx][ny] = true;
					grid[nx][ny] = grid[p.x][p.y] + 1;

				}
			}

		}

	}

	private static boolean isValid(int x, int y) {
		return 0 <= x && x < N && 0 <= y && y < M;
	}

}