Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = Gmap[h][w] + 1
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = Gmap[h][w] + 1
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = Gmap[h][w] + 1
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = Gmap[h][w] + 1
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())
sth, stw = 0, 0
glh, glw = H-1, W-1

INF = -1
Gmap = [list(input()) for _ in range(H)]
Dist = [[INF]*W for _ in range(H)]
direc = {(1,0), (-1,0), (0,1), (0,-1)}
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Dist[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.' and Dist[hs][ws]==INF:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.' and Dist[hs][ws]==INF:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
        hs, ws = h +0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.' and Dist[hs][ws]==INF:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.' and Dist[hs][ws]==INF:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())
sth, stw = 0, 0
glh, glw = H-1, W-1

INF = -1
Gmap = [list(input()) for _ in range(H)]
Dist = [[INF]*W for _ in range(H)]
direc = {(1,0), (-1,0), (0,1), (0,-1)}
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Dist[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        hs, ws = h + 0 , w + 1
        if Gmap[hs][ws]=='.' and Dist[hs][ws]==INF and ws<W:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
        hs, ws = h + 1 , w + 0
        if Gmap[hs][ws]=='.' and Dist[hs][ws]==INF and hs<H:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
        hs, ws = h +0 , w - 1
        if Gmap[hs][ws]=='.' and Dist[hs][ws]==INF and ws>=0:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
        hs, ws = h - 1 , w + 0
        if Gmap[hs][ws]=='.' and Dist[hs][ws]==INF and hs>=0:
            next_q.append([hs,ws])
            Dist[hs][ws] = Dist[h][w] + 1
            ret = max(ret, Dist[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())
sth, stw = 0, 0
glh, glw = H-1, W-1
#sth,stw = list(map(int,input().split()))
#sth, stw = sth-1, stw-1
#glh, glw = list(map(int,input().split()))
#glh, glw = glh-1, glw-1

INF = -1
Gmap = [list(input()) for _ in range(H)]
Dist = [[INF]*W for _ in range(H)]
#direc = [[1,0], [-1,0], [0,1], [0,-1]]
direc = {(1,0), (-1,0), (0,1), (0,-1)}
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Dist[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        for d in direc:
            hs, ws = h + d[0], w + d[1]
            if not (0<=hs<H and 0<=ws<W):
                continue
            if Gmap[hs][ws]=='.' and Dist[hs][ws]==INF:
                next_q.append([hs,ws])
                Dist[hs][ws] = Dist[h][w] + 1
                ret = max(ret, Dist[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()

Fixed submission:
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

INF = -1
H, W = map(int,input().split())
Gmap = [list(input()) for _ in range(H)]
Dist = [[INF]*W for _ in range(H)]
direc = [[1,0], [-1,0], [0,1], [0,-1]]

def dfs():
    q = deque([])
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                q.append([h,w])
                Dist[h][w]=0
    while len(q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = q.popleft()
        for d in direc:
            hs, ws = h + d[0], w + d[1]
            if not (0<=hs<H and 0<=ws<W):
                continue
            if Gmap[hs][ws]=='.' and Dist[hs][ws]==INF:
                q.append([hs,ws])
                Dist[hs][ws] = Dist[h][w] + 1

def main():
    dfs()
    print(max([max(Dist[h]) for h in range(H)]))

if __name__ == '__main__':
    main()

Fixed submission:
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

H, W = map(int,input().split())

INF = -1
Gmap = [list(input()) for _ in range(H)]
next_q = deque([])

def dfs_settings():
    #複数
    for h in range(H):
        for w in range(W):
            if Gmap[h][w]=='#':
                next_q.append([h,w])
                Gmap[h][w]=0

def dfs():
    ret = 0
    while len(next_q)!=0:
        #スタック取り出し(先頭)幅優先
        h,w = next_q.popleft()
        lv=Gmap[h][w]+1
        hs, ws = h + 0 , w + 1
        if ws<W and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 1 , w + 0
        if hs<H and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h + 0 , w - 1
        if ws>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
        hs, ws = h - 1 , w + 0
        if hs>=0 and Gmap[hs][ws]=='.':
            next_q.append([hs,ws])
            Gmap[hs][ws] = lv
            ret = max(ret, Gmap[hs][ws])
    return ret

def main():
    dfs_settings()
    ret = dfs()
    print(ret)

if __name__ == '__main__':
    main()