[프로그래머스] 게임 맵 최단거리(bfs)

import java.util.*;
class Solution {
    static int[] dx = {-1, 1, 0 , 0};
    static int[] dy = {0, 0, -1, 1};
    
    public int solution(int[][] maps) {
        int answer = 0;
        int[][] ch = new int[maps.length][maps[0].length];
        
        bfs(maps, ch);
        answer = ch[maps.length-1][maps[0].length-1];
        
        if(answer == 0){
            answer = -1;
        }else{
            return answer;
        }
        
        return answer;
    }
    
    public static void bfs(int[][] maps, int[][] ch){
        Queue<int[]> queue = new LinkedList<>();
        queue.offer(new int[]{0, 0});
        ch[0][0] =1;
        
        while(!queue.isEmpty()){
           int[] now= queue.poll();
            int x = now[0];
            int y = now[1];
            
            for(int i=0; i<4; i++){
                int nx = x + dx[i];
                int ny = y + dy[i];
                
                if(nx>=0 && nx<maps.length
                   && ny>=0 && ny<maps[0].length
                   && ch[nx][ny] == 0 && maps[nx][ny] == 1){
                    ch[nx][ny] = ch[x][y]+1;
                    queue.offer(new int[]{nx, ny});
                }
            }
            
        }
    }
    
}