Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = -1
  for j in range(W):
    if S[i][j] == "#":
      n = j
    L[i][j] = j-n
  n = W
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = j
    R[i][j] = n-j
for j in range(W):
  n = -1
  for i in range(H):
    if S[i][j] == "#":
      n = i
    U[i][j] = i-n
  n = H
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = i
    D[i][j] = n-i
#for i in range(H):
#  print(D[i])
r = 0
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = max(r, L[i][j]+R[i][j]+U[i][j]+D[i][j]-3)
print(r)


Fixed submission:
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = -1
  for j in range(W):
    if S[i][j] == "#":
      n = j
    L[i][j] = j-n
  n = W
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = j
    R[i][j] = n-j
for j in range(W):
  n = -1
  for i in range(H):
    if S[i][j] == "#":
      n = i
    U[i][j] = i-n
  n = H
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = i
    D[i][j] = n-i
#for i in range(H):
#  print(D[i])
r = 0
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = max(r, L[i][j]+R[i][j]+U[i][j]+D[i][j]-3)
print(r)

Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = -1
  for j in range(W):
    if S[i][j] == "#":
      n = j
    L[i][j] = j-n
  n = W
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = j
    R[i][j] = n-j
for j in range(W):
  n = -1
  for i in range(H):
    if S[i][j] == "#":
      n = i
    U[i][j] = i-n
  n = H
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = i
    D[i][j] = n-i
#for i in range(H):
#  print(D[i])
rs = []
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = L[i][j]+R[i][j]+U[i][j]+D[i][j]-3
      rs.append(r)
r = max(rs)
print(r)


Fixed submission:
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = -1
  for j in range(W):
    if S[i][j] == "#":
      n = j
    L[i][j] = j-n
  n = W
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = j
    R[i][j] = n-j
for j in range(W):
  n = -1
  for i in range(H):
    if S[i][j] == "#":
      n = i
    U[i][j] = i-n
  n = H
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = i
    D[i][j] = n-i
#for i in range(H):
#  print(D[i])
r = 0
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = max(r, L[i][j]+R[i][j]+U[i][j]+D[i][j]-3)
print(r)

Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = 0
  for j in range(W):
    if S[i][j] == "#":
      n = 0
    else:
      n += 1
    L[i][j] = n
  n = 0
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = 0
    else:
      n += 1
    R[i][j] = n
for j in range(W):
  n = 0
  for i in range(H):
    if S[i][j] == "#":
      n = 0
    else:
      n += 1
    U[i][j] = n
  n = 0
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = 0
    else:
      n += 1
    D[i][j] = n
#for i in range(H):
#  print(U[i])
rs = []
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = L[i][j]+R[i][j]+U[i][j]+D[i][j]-3
      rs.append(r)
r = max(rs)
print(r)


Fixed submission:
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = -1
  for j in range(W):
    if S[i][j] == "#":
      n = j
    L[i][j] = j-n
  n = W
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = j
    R[i][j] = n-j
for j in range(W):
  n = -1
  for i in range(H):
    if S[i][j] == "#":
      n = i
    U[i][j] = i-n
  n = H
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = i
    D[i][j] = n-i
#for i in range(H):
#  print(D[i])
r = 0
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = max(r, L[i][j]+R[i][j]+U[i][j]+D[i][j]-3)
print(r)

Buggy python submission (verdict: Time Limit Exceeded):
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
N = [[-1]*W for i in range(H)]
for i in range(H):
  Bs = [-1]
  for j in range(W):
    if S[i][j] == "#":
      Bs.append(j)
  Bs.append(W)
  for k in range(1, len(Bs)):
    n = Bs[k]-Bs[k-1]-1
    for j in range(Bs[k-1]+1, Bs[k]):
      N[i][j] = n
M = [[-1]*W for i in range(H)]
for j in range(W):
  Bs = [-1]
  for i in range(H):
    if S[i][j] == "#":
      Bs.append(i)
  Bs.append(H)
  for k in range(1, len(Bs)):
    n = Bs[k]-Bs[k-1]-1
    for i in range(Bs[k-1]+1, Bs[k]):
      M[i][j] = n
rs = []
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = N[i][j]+M[i][j]-1
      rs.append(r)
r = max(rs)
print(r)


Fixed submission:
H, W = map(int, input().split())
S = []
for i in range(H):
  ss = input()
  S.append(ss)
L = [[-1]*W for i in range(H)]
R = [[-1]*W for i in range(H)]
U = [[-1]*W for i in range(H)]
D = [[-1]*W for i in range(H)]
for i in range(H):
  n = -1
  for j in range(W):
    if S[i][j] == "#":
      n = j
    L[i][j] = j-n
  n = W
  for j in reversed(range(W)):
    if S[i][j] == "#":
      n = j
    R[i][j] = n-j
for j in range(W):
  n = -1
  for i in range(H):
    if S[i][j] == "#":
      n = i
    U[i][j] = i-n
  n = H
  for i in reversed(range(H)):
    if S[i][j] == "#":
      n = i
    D[i][j] = n-i
#for i in range(H):
#  print(D[i])
r = 0
for i in range(H):
  for j in range(W):
    if S[i][j] == ".":
      r = max(r, L[i][j]+R[i][j]+U[i][j]+D[i][j]-3)
print(r)