[백준] 토마토 7569.py

import sys
from collections import deque
from copy import deepcopy
width, height, depth = map(int, sys.stdin.readline().split())
maps = []
starts = []
no_zero = True
def bfs(starts, maps, depth, height, width):
    # 가로, 세로, 높이로 각각 이동
    dirs = [(1,0,0),(-1,0,0),(0,1,0),(0,-1,0),(0,0,1),(0,0,-1)]
    queue = deque()
    queue.extend(starts)
    while queue:
        cd, ch, cw, cnt = queue.popleft()
        for dd, dh, dw in dirs:
            nd, nh, nw = cd + dd, ch + dh, cw + dw
            if 0 <= nh < height and 0 <= nd < depth and 0 <= nw < width and maps[nd][nh][nw] == 0:
                maps[nd][nh][nw] = 1
                queue.append((nd, nh, nw, cnt + 1))
    return cnt

# 토마토가 익을 수 있는 환경인지 아닌지 체크하는 함수
def check(maps, depth, height, width):
    for d in range(depth):
        for h in range(height):
            for w in range(width):
                if maps[d][h][w] == 0:
                    return -1
    return 0

for d in range(depth):
    temp = []
    for h in range(height):
        a = list(map(int, sys.stdin.readline().split()))
        for w in range(width):
            if a[w] == 0:
                no_zero = False
            if a[w] == 1:
                starts.append((d,h,w,0))
        temp.append(deepcopy(a))
    maps.append(deepcopy(temp))

# 처음부터 0이 하나도 없을 경우 더 계산할 필요가 없다.
if no_zero:
    print(0)
    exit(0)
    
count = bfs(starts, maps, depth, height, width)

if check(maps, depth, height, width) != 0:
    print(-1)
else:
    print(count)