[프로그래머스] Lv 2. 게임 맵 최단거리

def solution(maps):
    answer = 0
    #상,하,좌,우
    X = len(maps[0])
    Y = len(maps)
    
    visited = [[False for _ in range(X)] for _ in range(Y)]
    dx = [0,0,-1,1]
    dy = [-1,1,0,0]
    queue = []

    def bfs(x, y):
        visited[y][x] = True
        queue.append([y, x])

        while queue:
            
            current = queue.pop(0)
            y, x = current[0], current[1]
            for i in range(4):
                ny = y + dy[i]
                nx = x + dx[i]
                if 0<= ny < Y and 0<= nx < X and maps[ny][nx] == 1:
                    
                    if visited[ny][nx] == False:
                        visited[ny][nx] = True
                        queue.append([ny, nx])
                        maps[ny][nx] = maps[y][x] + 1
                        
    bfs(0, 0)
    if maps[Y-1][X-1] == 1:
        return -1
    else:
        return maps[Y-1][X-1]