[BOJ] 백준 2178 - 미로탐색 (JAVA)

 

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 Main2178_미로탐색 {
    private static int[][] map;
    private static boolean[][] visited;
    private static int[] dx = {-1, 1 , 0 , 0};
    private static int[] dy = {0, 0 , 1 , -1};
    private static int N;
    private static int M;
    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+1][M+1];
        visited = new boolean[N+1][M+1];
        
        for (int i = 1; i < N+1; i++) {
            String str = br.readLine();
            for (int j = 1; j < M+1; j++) {
                map[i][j] = str.charAt(j-1)-'0';
            }
        }
        
        bfs(1,1,1);
        
        
    }//end of main
 
    public static void bfs(int x, int y, int cnt) {
        int count = 1;
        Queue<Pair> q = new LinkedList<>();
        visited[x][y] = true;
        q.add(new Pair(x, y , cnt));
        
        while(!q.isEmpty()) {            
            Pair p = q.poll();
            count = p.cnt;
            if(p.x == N && p.y ==M) {
                System.out.println(count);
                break;
            }
            
            
            for (int i = 0; i < dx.length; i++) {
                int nx = p.x + dx[i];
                int ny = p.y + dy[i];
                if(nx > N || ny > M || visited[nx][ny] || map[nx][ny] ==0  ) continue;
                else {
                    visited[nx][ny] = true;
                    q.add(new Pair(nx,ny, count+1));
                }
            }
            
        }
    }
    
    static class Pair{
        int x;
        int y;
        int cnt;
        public Pair(int x, int y, int cnt) {
            super();
            this.x = x;
            this.y = y;
            this.cnt = cnt;
        }
        
        
    }
}//end of class