[백준] 2178번 미로 탐색

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

2178번: 미로 탐색

 

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

class Node {
    int y;
    int x;

    Node(int y, int x) {
        this.y = y;
        this.x = x;
    }
}

public class Main {

    static int N;
    static int M;
    static int[][] map;
    static boolean[][] visit;

    static int[] dy = { 0, 1, 0, -1 };
    static int[] dx = { 1, 0, -1, 0 };

    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        N = Integer.parseInt(st.nextToken());
        M = Integer.parseInt(st.nextToken());

        map = new int[N][M];
        visit = new boolean[N][M];

        for (int i = 0; i < N; i++) {
            String input = br.readLine();
            for (int j = 0; j < M; j++) {
            	map[i][j] = input.charAt(j) - '0';
            }
        }

        bfs(0, 0);
        System.out.println(map[N-1][M-1]);

    }

    public static void bfs(int y, int x) {
        Queue<Node> q = new LinkedList<>();
        q.offer(new Node(0, 0));
        visit[0][0] = true;

        while (!q.isEmpty()) {
        Node node = q.poll();
        int ny = node.y;
        int nx = node.x;

            for (int i = 0; i < 4; i++) {
                int nextY = ny + dy[i];
                int nextX = nx + dx[i];

                // 벽의 범위 벗어남
                if (nextY < 0 || nextY >= N || nextX < 0 || nextX >= M) {
                    continue;
                }

                // 맵이 0이거나, 이미 방문했을 대 통과
                if (map[nextY][nextX] == 0 || visit[nextY][nextX]) {
                    continue;
                }

                // 큐에 추가
                q.offer(new Node(nextY, nextX));
                // 방문처리
                visit[nextY][nextX] = true;
                // 거리 누적
                map[nextY][nextX] = map[ny][nx] + 1;
            }

        }
    }

}