LeetCode#36 Valid Sudoku

Problem Definition:

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

The Sudoku board could be partially filled, where empty cells are filled with the character '.'.

A partially filled sudoku which is valid.

Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

Solution: 用仨字典，一次扫描，针对n x n 的Sudoku，时间复杂度O(n^2).

 1 def isValidSudoku( board ):

 2         col,row,block={},{},{}

 3         for i in range(9):

 4             for j in range(9):

 5                 if board[i][j]=='.':

 6                     continue

 7                 d=board[i][j]

 8                 T=row.get(str(i)+d,False)

 9                 if T:

10                     return False

11                 else:

12                     row[str(i)+d]=True

13                 T=col.get(str(j)+d,False)

14                 if T:

15                     return False

16                 else:

17                     col[str(j)+d]=True

18                 T=block.get(str((i/3)*3+j/3)+d,False)

19                 if T:

20                     return False

21                 else:

22                     block[str((i/3)*3+j/3)+d]=True

23         return True