Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1

        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq
    nq = 0
    ans += 1
print(ans)





Fixed submission:
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1

        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq
    nq = 0
    ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1
        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq

    ans += 1
print(ans)





Fixed submission:
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1

        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq
    nq = 0
    ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()
next_que =  deque()

for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            next_que.append((h,w))
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
que = next_que
while cot != H*W:
    que = copy.deepcopy(next_que)
    next_que = deque()
    while que:
        h,w = que.popleft()
        for temp in go:
            gx,gy = temp
            nx = w + gx
            ny = h + gy
            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                gone[ny][nx] = 1
                next_que.append( (ny,nx))
                cot += 1
    ans += 1
print(ans)





Fixed submission:
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1

        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq
    nq = 0
    ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
import sys
from collections import defaultdict
import copy
import numpy as np
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = np.zeros((H,W))
cot = 0
que = deque()
next_que =  deque()

for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            next_que.append((h,w))
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
que = next_que
while cot != H*W:
    que = copy.deepcopy(next_que)
    next_que = deque()
    while que:
        h,w = que.popleft()
        for temp in go:
            gx,gy = temp
            nx = w + gx
            ny = h + gy
            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                gone[ny][nx] = 1
                next_que.append( (ny,nx))
                cot += 1
    ans += 1
print(ans)





Fixed submission:
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1

        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq
    nq = 0
    ans += 1
print(ans)

Buggy python submission (verdict: Runtime Error):
from collections import deque
import sys
from collections import defaultdict
import copy
import numpy as np
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = np.zeros((H,W))
cot = 0
que = deque()
next_que =  deque()

for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            next_que.append((h,w))
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
que = next_que
while cot != H*W:
    que = copy.deepcopy(next_que)
    next_que = deque()
    while que:
        h,w = que.popleft()
        for temp in go:
            gx,gy = temp
            nx = w + gx
            ny = h + gy
            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                gone[ny][nx] = 1
                next_que.append( (ny,nx))
                cot += 1
    ans += 1
print(ans)





Fixed submission:
from collections import deque
import sys
from collections import defaultdict
import copy
# input = sys.stdin.readline



H, W = map(int, input().split())
C = [list(input()) for _ in range(H)]
gone = [[0] * W for _ in range(H)]
cot = 0
que = deque()

que_count = 0
for h in range(H):
    for w in range(W):
        if C[h][w] == "#":
            gone[h][w] = 1
            que.append((h,w))
            que_count += 1
            cot += 1
INF = 10 ** 9
go = [[1, 0], [0, 1], [-1, 0], [0, -1]]
ans  = 0
nq = 0
while cot != H*W:
    while que_count != 0 and cot != H*W:
        h,w = que.popleft()
        que_count -= 1

        for temp in go:
            # この時，実際に行くのかは不明
            gx,gy = temp
            nx = w + gx
            ny = h + gy

            if 0<= nx < W and 0<= ny < H and gone[ny][nx] != 1: #行って無かったら，行く
                # この時に実際に移動する
                gone[ny][nx] = 1
                que.append( (ny,nx))
                nq += 1
                cot += 1
    que_count = nq
    nq = 0
    ans += 1
print(ans)