[백준] 7576번 토마토 (파이썬)

7576번: 토마토

 

 

코드

from collections import deque

m, n = map(int, input().split())
tree = list(list(map(int, input().split())) for _ in range(n))

que = deque([])

dx = [1,-1,0,0]
dy = [0,0,1,-1]

def bfs():
    while que:
        x, y = que[0][0], que[0][1]
        del que[0]
        for i in range(4):
            n_x = x + dx[i]
            n_y = y + dy[i]
            if 0 <= n_x < n and 0 <= n_y < m:
                if tree[n_x][n_y] == 0:
                    que.append([n_x, n_y])
                    tree[n_x][n_y] = tree[x][y] +1

for i in range(n):
    for j in range(m):
        if tree[i][j] == 1:
            que.append([i,j])

bfs()
min = 0
zero = False

for i in range(n):
    for j in range(m):
        if tree[i][j] == 0:
            zero = True
            break
        elif tree[i][j] > min and tree[i][j] != -1:
            min = tree[i][j]

if zero == True:
    print(-1)
elif min == 1:
    print(0)
else:
    print(min -1)