programmers_게임 맵 최단거리_java

https://school.programmers.co.kr/learn/courses/30/lessons/1844

프로그래머스

import java.util.*;

class Solution {
    private static int[][] delta = {{0,1}, {0, -1}, {1, 0}, {-1,0}};
    
    public int solution(int[][] maps) {
        int answer = 0;
        
        answer = bfs(maps, maps[0].length, maps.length);
        return answer;
    }
    
    public int bfs(int[][] maps, int width, int height){
        int cnt = 0;
        Queue<Point> queue = new LinkedList<>();        
        boolean[][] visited = new boolean[height+1][width+1];
        queue.offer(new Point(1,1));
        
        while(!queue.isEmpty()){
            int size = queue.size();
            cnt++; // 이동 횟수
            for(int i = 0; i<size; i++){
                Point now = queue.poll();                
                
                if(visited[now.y][now.x]) continue;                
                visited[now.y][now.x] = true;
                
                if(now.y == height && now.x == width){ // 목적지 도착
                    return cnt;
                }
                
                for(int j = 0; j<4; j++){
                    int nexty = now.y + delta[j][0];
                    int nextx = now.x + delta[j][1];
                    
                    if(0<nexty && nexty<=height && 0<nextx && nextx<=width && maps[nexty-1][nextx-1] == 1 && !visited[nexty][nextx]){
                        queue.offer(new Point(nexty, nextx));
                    }
                }
            }
        }
        return -1;
    }
    
    public class Point{
        int y, x;
        public Point(int y, int x){
            this.y = y;
            this.x = x;
        }
    }
    
}