# 7576번 – 토마토

## 문제

https://www.acmicpc.net/problem/7576

## 코드

``````from collections import deque
from copy import deepcopy

m, n = map(int, input().split())
board = [list(map(int, input().split())) for _ in range(n)]
board = [[-1]*m] + board + [[-1]*m]
for y in range(len(board)): board[y] = [-1] + board[y] + [-1]
dyx = [(-1, 0), (0, 1), (1, 0), (0, -1)]

global m, n, board
day = BFS()
# 다 익었어야 했는데, 안익었다면...
if 토마토가다익었나(board) is False: return -1
return day

def 익은토마토찾기(board):
좌표들 = []
for y in range(len(board)):
for x in range(len(board[y])):
if board[y][x] == 1: 좌표들.append((y, x))
return 좌표들

def 토마토가다익었나(board):
for y in range(len(board)):
for x in range(len(board[y])):
if board[y][x] == 0: return False
return True

def BFS():
global board
Q = deque(익은토마토찾기(board))
NQ = deque()
day = 0
while(len(Q) > 0):
y, x = Q.popleft()
for dy, dx in dyx:
ny, nx = dy+y, dx+x
if board[ny][nx] == 0:
board[ny][nx] = 1
NQ.append((ny, nx))
if len(Q) == 0:
if len(NQ) > 0:
Q = deepcopy(NQ)
NQ = deque()
day += 1
else: break
return day