```
def isValidSudoku(self, board):
k = 9
row = [0] * k
col = [0] * k
cube = [[0] * 3 for _ in range(3)]
for i in range(k):
for j in range(k):
if board[i][j] != '.':
tmp = 1 << int(board[i][j])
if tmp & row[i] or tmp & col[j] or tmp & cube[i / 3][j / 3]:
return False
row[i] |= tmp
col[j] |= tmp
cube[i / 3][j / 3] |= tmp
return True
```