programmers_미로 탈출_java

https://school.programmers.co.kr/learn/courses/30/lessons/159993

프로그래머스

import java.util.*;

class Solution {
    
    private static int[][] delta = {{0,1}, {1, 0}, {0, -1}, {-1,0}};
    
    public int solution(String[] maps) {
        int answer = 0;
        
        int width = maps[0].length();
        int height = maps.length;
        int[] start = new int[2];
        
        for(int i = 0; i<height; i++){
            for(int j = 0; j<width; j++){
                if(maps[i].charAt(j) == 'S'){
                    start[0] = i;
                    start[1] = j;
                    break;
                }             
            }
        }
        
        answer = bfs(maps, width, height, start, 'L');
        
        return answer;
    }
    
    public int bfs(String[] maps, int width, int height, int[] start, char target){
        boolean[][] visited = new boolean[height][width];
        Queue<int[]> queue = new LinkedList<>();
        queue.offer(start);
        visited[start[0]][start[1]] = true;

        int cnt = 0;
        while(!queue.isEmpty()){
            int size = queue.size();

            for(int i = 0; i<size; i++){
                int[] now = queue.poll();

                if(maps[now[0]].charAt(now[1]) == target){
                    if(target == 'L'){
                        int tmp = bfs(maps, width, height, now, 'E');
                        if(tmp == -1) return -1;
                        cnt = cnt + tmp;
                    }
                    return cnt;
                }

                for(int j = 0; j<4; j++){ // 4방 탐색
                    int[] next = new int[2];
                    next[0] = now[0] + delta[j][0];
                    next[1] = now[1] + delta[j][1];

                    if(0<=next[0] && next[0]<height && 0<=next[1] && next[1]<width && maps[next[0]].charAt(next[1]) != 'X' && !visited[next[0]][next[1]]){
                        visited[next[0]][next[1]] = true;
                        queue.offer(next);
                    }
                }
            }
            cnt++;
        }
        
        return -1;
    }    
}