Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.extend([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []


for i in range(1, w + 1):
    for j in range(1, h + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)


Fixed submission:
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []

for i in range(1, h + 1):
    for j in range(1, w + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h + 2):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []


for i in range(1, w + 1):
    for j in range(1, h + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)


Fixed submission:
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []

for i in range(1, h + 1):
    for j in range(1, w + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []


for i in range(1, w + 1):
    for j in range(1, h + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)


Fixed submission:
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []

for i in range(1, h + 1):
    for j in range(1, w + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []


for i in range(1, w + 1):
    for j in range(1, h + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while q:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)


Fixed submission:
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []

for i in range(1, h + 1):
    for j in range(1, w + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []


for i in range(1, w + 1):
    for j in range(1, h + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while q:
    qq = []
    count += 1
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append(i, j + 1)
    q = qq

print(count)


Fixed submission:
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []

for i in range(1, h + 1):
    for j in range(1, w + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-
from functools import reduce

h, w = map(int, input().split())
a = []
b = set([])

for i in range(h):
    a.append(list(input()))
    for j in range(w):
        if (a[i][j] == '#'):
            b.add((i, j))


def addBlack(bl, t):
    bl.add(t)
    if t[0] - 1 >= 0:
        bl.add((t[0] - 1, t[1]))
    if t[0] + 1 < w:
        bl.add((t[0] + 1, t[1]))
    if t[1] - 1 >= 0:
        bl.add((t[0], t[1] - 1))
    if t[1] + 1 < h:
        bl.add((t[0], t[1] + 1))
    return bl


count = 0
while(len(b) < h * w):
    count += 1
    b = reduce(addBlack, b, set([]))

print(count)


Fixed submission:
# -*- coding: utf-8 -*-
h, w = map(int, input().split())
a = []
a = [[True] * (w + 2)]
for i in range(h):
    a.append([True] + [x == '#' for x in input()] + [True])
a.append([True] * (w + 2))
q = []

for i in range(1, h + 1):
    for j in range(1, w + 1):
        if a[i][j]:
            q.append((i, j))

count = 0
while True:
    qq = []
    for i, j in q:
        if not a[i-1][j]:
            a[i-1][j] = True
            qq.append((i - 1, j))
        if not a[i+1][j]:
            a[i+1][j] = True
            qq.append((i + 1, j))
        if not a[i][j-1]:
            a[i][j-1] = True
            qq.append((i, j - 1))
        if not a[i][j+1]:
            a[i][j+1] = True
            qq.append((i, j + 1))
    q = qq
    if len(q) <= 0:
        break
    count += 1

print(count)