Buggy python submission (verdict: Time Limit Exceeded):
import sys
# from bisect import *
# from collections import *
# from copy import deepcopy
# from heapq import *
# from itertools import *
# from math import *
# from operator import *
# from pprint import *

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    grid = [list(input().rstrip()) for _ in range(H)]
    q = []
    visited = [[False]*W for _ in range(H)]
    for y in range(H):
        for x in range(W):
            if grid[y][x] == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                ny = y+dy
                nx = x+dx
                if 0<=ny<H and 0<=nx<W and not visited[ny][nx]:
                    new_q.append((ny,nx))
                    visited[ny][nx] = True
        if new_q:
            q = new_q
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):

import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    grid = [list(input().rstrip()) for _ in range(H)]
    q = []
    visited = [[False]*W for _ in range(H)]
    for y in range(H):
        for x in range(W):
            if grid[y][x] == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                ny = y+dy
                nx = x+dx
                if 0<=ny<H and 0<=nx<W and not visited[ny][nx]:
                    new_q.append((ny,nx))
                    visited[ny][nx] = True
        if new_q:
            q = new_q
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input().rstrip()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        for x, val in enumerate(list(input().rstrip())):
            if val == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            if 0 < y and not visited[y-1][x]:
                new_q.append((y-1,x))
                visited[y-1][x] = True
            if y < H-1 and not visited[y+1][x]:
                new_q.append((y+1,x))
                visited[y+1][x] = True
            if 0 < x and not visited[y][x-1]:
                new_q.append((y,x-1))
                visited[y][x-1] = True
            if x < W-1 and not visited[y][x+1]:
                new_q.append((y,x+1))
                visited[y][x+1] = True
        if new_q:
            q = new_q[:]
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        for x, val in enumerate(list(input().rstrip())):
            if val == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                ny = y+dy
                nx = x+dx
                if 0<=ny<H and 0<=nx<W and not visited[ny][nx]:
                    new_q.append((ny,nx))
                    visited[ny][nx] = True
        if new_q:
            q = new_q[:]
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        for x, val in enumerate(list(input().rstrip())):
            if val == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                ny = y+dy
                nx = x+dx
                if 0<=ny<H and 0<=nx<W and not visited[ny][nx]:
                    new_q.append((ny,nx))
                    visited[ny][nx] = True
        if new_q:
            q = new_q[:]
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    grid = [list(input().rstrip()) for _ in range(H)]
    q = []
    visited = [[False]*W for _ in range(H)]
    for y in range(H):
        for x in range(W):
            if grid[y][x] == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                ny = y+dy
                nx = x+dx
                if 0<=ny<H and 0<=nx<W and not visited[ny][nx] and grid[ny][nx] == '.':
                    new_q.append((ny,nx))
                    visited[ny][nx] = True
        if new_q:
            q = new_q
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    grid = [list(input().rstrip()) for _ in range(H)]
    q = []
    visited = [[False]*W for _ in range(H)]
    for y in range(H):
        for x in range(W):
            if grid[y][x] == '#':
                q.append((y,x))
                visited[y][x] = True
    ans = -1
    while q:
        ans += 1
        new_q = []
        for y,x in q:
            for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                ny = y+dy
                nx = x+dx
                if 0<=ny<H and 0<=nx<W and not visited[ny][nx] and grid[ny][nx] == '.':
                    new_q.append((ny,nx))
                    visited[ny][nx] = True
        if new_q:
            q = new_q[:]
        else:
            break
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    grid = [list(input().rstrip()) for _ in range(H)]
    q = deque()
    visited = [[False]*W for _ in range(H)]
    black_cnt = 0
    ans = 0
    for y in range(H):
        for x in range(W):
            if grid[y][x] == '#':
                q.append((y,x,0))
                visited[y][x] = True
                black_cnt += 1
    while q:
        y,x,step = q.popleft()
        ans = step
        for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
            ny = y+dy
            nx = x+dx
            if 0<=ny<H and 0<=nx<W and not visited[ny][nx]:
                q.append((ny,nx,step+1))
                visited[ny][nx] = True
                black_cnt += 1
    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import *
from collections import *
from copy import deepcopy
from heapq import *
from itertools import *
from math import *
from operator import *
from pprint import *
import numpy as np

sys.setrecursionlimit(10**8)

input = sys.stdin.readline

def main():
    """ main """
    H,W = map(int, input().split())
    grid = [list(input().rstrip()) for _ in range(H)]
    ans = 0
    while True:
        new_grid = [['.']*W for _ in range(H)]
        black_cnt = 0
        for y in range(H):
            for x in range(W):
                if grid[y][x] == '#':
                    black_cnt += 1
                    new_grid[y][x] = '#'
                    for dy,dx in [(1,0),(-1,0),(0,1),(0,-1)]:
                        ny = y+dy
                        nx = x+dx
                        if 0<=ny<H and 0<=nx<W:
                            new_grid[ny][nx] = '#'
        if black_cnt == W*H: break

        ans += 1
        grid = deepcopy(new_grid)

    print(ans)

if __name__ == '__main__':
    main()

Fixed submission:
def main():
    H, W = map(int,input().split())
    visited = [[False]*W for _ in range(H)]
    q = []
    for y in range(H):
        S = input()
        for x, s in enumerate(S):
            if s == "#":
                q.append((y, x))
                visited[y][x] = True

    ans = -1
    while q:
        ans += 1
        nq = []
        for y, x in q:
            if 0 < x and not visited[y][x-1]:
                visited[y][x-1] = True
                nq.append((y,x-1))
            if x < W-1 and not visited[y][x+1]:
                visited[y][x+1] = True
                nq.append((y,x+1))
            if 0 < y and not visited[y-1][x]:
                visited[y-1][x] = True
                nq.append((y-1, x))
            if y < H-1 and not visited[y+1][x]:
                visited[y+1][x] = True
                nq.append((y+1,x))
        if nq:
            q = nq
        else:
            break

    print(ans)

if __name__ == '__main__':
    main()