new_contents: """Leetcode 36. Valid Sudoku
  Medium
  
  URL: https://leetcode.com/problems/valid-sudoku/
  
  Determine if a 9x9 Sudoku board is valid. Only the filled cells need to be 
  validated according to the following rules:
  
  Each row must contain the digits 1-9 without repetition.
  Each column must contain the digits 1-9 without repetition.
  Each of the 9 3x3 sub-boxes of the grid must contain the digits 1-9 without 
  repetition.
  
  A partially filled sudoku which is valid.
  
  The Sudoku board could be partially filled, where empty cells are filled with 
  the character '.'.
  
  Example 1:
  Input:
  [
    ["5","3",".",".","7",".",".",".","."],
    ["6",".",".","1","9","5",".",".","."],
    [".","9","8",".",".",".",".","6","."],
    ["8",".",".",".","6",".",".",".","3"],
    ["4",".",".","8",".","3",".",".","1"],
    ["7",".",".",".","2",".",".",".","6"],
    [".","6",".",".",".",".","2","8","."],
    [".",".",".","4","1","9",".",".","5"],
    [".",".",".",".","8",".",".","7","9"]
  ]
  Output: true
  
  Example 2:
  Input:
  [
    ["8","3",".",".","7",".",".",".","."],
    ["6",".",".","1","9","5",".",".","."],
    [".","9","8",".",".",".",".","6","."],
    ["8",".",".",".","6",".",".",".","3"],
    ["4",".",".","8",".","3",".",".","1"],
    ["7",".",".",".","2",".",".",".","6"],
    [".","6",".",".",".",".","2","8","."],
    [".",".",".","4","1","9",".",".","5"],
    [".",".",".",".","8",".",".","7","9"]
  ]
  Output: false
  Explanation: Same as Example 1, except with the 5 in the top left corner 
  being modified to 8. Since there are two 8's in the top left 3x3 sub-box, 
  it is invalid.
  
  Note:
  - A Sudoku board (partially filled) could be valid but is not necessarily solvable.
  - Only the filled cells need to be validated according to the mentioned rules.
  - The given board contain only digits 1-9 and the character '.'.
  - The given board size is always 9x9.
  """
  
  class Solution(object):
      def isValidSudoku(self, board):
          """
          :type board: List[List[str]]
          :rtype: bool
          """
          pass
  
  
  def main():
  	pass
  
  
  if __name__ == '__main__':
  	main()
  
subject: Add lc036_valid_sudoku.py