ValidSoduku.py

'''
sudoku:
Grid 9 * 9, each row and column have the 1-9 numbers occuring only once
each row, each column, each 3*3 subblock must all the 1-9 but unique numbers 
The cells which don't have numbers are filled with '.' 
given a solution of sudoku, check whether it is valid
'''
class Sudoku(object):
 def __init__(self):
 self.board_rows = [['.' for i in range(9)] for j in range(9)]
 
 def isSolved(self):
 '''Check whether the solution is valid sudoku

 for each row, each column, each 3*3 block, they only have 1-9 unique numbers
 with only appear once
 
 Returns:
 True or False whether the solution is valid sudoku
 '''
 validSet = set(['1','2','3','4','5','6','7','8','9'])
 # check all the rows
 for row in self.board_rows:
 if set(row) != validSet:
 return False
 # check all the columns
 for c in range(9):
 # column = [self.board_rows[r][c] for r in range(9)]
 if set([row[c] for row in self.board_rows]) != validSet:
 return False
 # check all the blocks
 # index = [0,3,6]
 for i in range(3):
 for j in range(3):
 block = []
 for plusi in range(3):
 for plusj in range(3):
 block.append(self.board_rows[3 * i + plusi][3 * j + plusj]) 
 if set(block) != validSet:
 return False
 return True