Buggy python submission (verdict: Time Limit Exceeded):
h, w = map(int, input().split())

s = [input() for _ in range(h)]

x_inf = [[0 for i in range(w)] for j in range(h)]
y_inf = [[0 for i in range(w)] for j in range(h)]
for i in range(h):
    p = -1
    for j in range(w):
        if s[i][j]=="#":
            p = j
        else:
            x_inf[i][j] = p

for i in range(h):
    p = w
    for j in range(-1,-w-1,-1):
        if s[i][j]=="#":
            p = w+j
        else:
            x_inf[i][j] -= p-1

for i in range(w):
    p = -1
    for j in range(h):
        if s[j][i]=="#":
            p = j
        else:
            y_inf[j][i] = p

for i in range(w):
    p = h
    for j in range(h-1,-1,-1):
        if s[j][i]=="#":
            p = j
        else:
            y_inf[j][i] -= p-1
result = []
for i in range(h):
    for j in range(w):
        if s[i][j]==".":
            result.append(x_inf[i][j]+y_inf[i][j]+1)
print(-min(result))

Fixed submission:
h, w = map(int, input().split())

s = [input() for _ in range(h)]

x_inf = [[0 for i in range(w)] for j in range(h)]
y_inf = [[0 for i in range(w)] for j in range(h)]
for i in range(h):
    p = -1
    for j in range(w):
        if s[i][j]=="#":
            p = j
        else:
            x_inf[i][j] = p

for i in range(h):
    p = w
    for j in range(-1,-w-1,-1):
        if s[i][j]=="#":
            p = w+j
        else:
            x_inf[i][j] -= p-1

for i in range(w):
    p = -1
    for j in range(h):
        if s[j][i]=="#":
            p = j
        else:
            y_inf[j][i] = p

for i in range(w):
    p = h
    for j in range(h-1,-1,-1):
        if s[j][i]=="#":
            p = j
        else:
            y_inf[j][i] -= p-1
result = []
for i in range(h):
    for j in range(w):
        if s[i][j]==".":
            result.append(x_inf[i][j]+y_inf[i][j]+1)
print(-min(result))

Buggy python submission (verdict: Time Limit Exceeded):
h, w = map(int, input().split())

s = [input() for _ in range(h)]

result = []
for i in range(h):
    for j in range(w):
        if s[i][j] == "#":
            continue
        else:
            c = 1
            x = 1
            while i+x < h and s[i+x][j] == ".":
                x += 1
                c += 1
            x = 1
            while i-x >= 0 and s[i-x][j] == ".":
                x += 1
                c += 1
            y = 1
            while j+y < w and s[i][j+y] == ".":
                y += 1
                c += 1
            y = 1
            while j-y >= 0 and s[i][j-y] == ".":
                y += 1
                c += 1
        result.append(c) 
print(max(result)) 

Fixed submission:
h, w = map(int, input().split())

s = [input() for _ in range(h)]

x_inf = [[0 for i in range(w)] for j in range(h)]
y_inf = [[0 for i in range(w)] for j in range(h)]
for i in range(h):
    p = -1
    for j in range(w):
        if s[i][j]=="#":
            p = j
        else:
            x_inf[i][j] = p

for i in range(h):
    p = w
    for j in range(-1,-w-1,-1):
        if s[i][j]=="#":
            p = w+j
        else:
            x_inf[i][j] -= p-1

for i in range(w):
    p = -1
    for j in range(h):
        if s[j][i]=="#":
            p = j
        else:
            y_inf[j][i] = p

for i in range(w):
    p = h
    for j in range(h-1,-1,-1):
        if s[j][i]=="#":
            p = j
        else:
            y_inf[j][i] -= p-1
result = []
for i in range(h):
    for j in range(w):
        if s[i][j]==".":
            result.append(x_inf[i][j]+y_inf[i][j]+1)
print(-min(result))