36. Valid Sudoku

# Medium

Easy

Solution:

1. Judge repeatition in horizon.

2. Judge repeatition in vertical.

3. Judge repeatition in 3x3 blocks.

Python

class Solution(object):
    def isValidSudoku(self, board):
        """
        :type board: List[List[str]]
        :rtype: bool
        """

        # vertical
        for i in range(9):
            if self.vertical(board, i) == False:
                return False
        
        # horizontal
        for i in range(9):
            if self.horizon(board, i) == False:
                return False
            
        # blocks
        for i in range(3):
            for j in range(3):
                if self.block(board, i, j) == False:
                    return False
        
        return True
    
    def vertical(self, board, i):
        temp = []
        for x in range(9):
            if board[x][i] != '.':
                if board[x][i] in temp:
                    return False
                else:
                    temp.append(board[x][i])
        return True
        
    def horizon(self, board, i):
        temp = []
        for x in range(9):
            if board[i][x] != '.':
                if board[i][x] in temp:
                    return False
                else:
                    temp.append(board[i][x])
        return True
    
    def block(self, board, i, j):
        #print(sub)
        temp = []
        for x in range(i*3, (i+1)*3):
            for y in range(j*3, (j+1)*3):
                if board[x][y] != '.':
                    if board[x][y] in temp:
                        return False
                    else:
                        temp.append(board[x][y])
        return True

list[x] represents xth row in Python.

list[:][x] doesn't represent xth column in Python.