这个解法告诉我们读题要精确，且例证了多维数组的重要性。

# Sudoku [http://en.wikipedia.org/wiki/Sudoku]

# A valid sudoku square satisfies these

# two properties:

# 1. Each column of the square contains each of the whole numbers from 1 to n exactly once.

# 2. Each row of the square contains each of the whole numbers from 1 to n exactly once.

# You may assume the the input is square and contains at least one row and column.

def check_sudoku(m):

　　n = len(m) # set the size of the matrix

　　for x in range(n):

　　row,col = [],[] # use lists so I can use "in"

　　for y in range(n):

　　　　row.append(m[x][y]) # build row and column list

　　　　col.append(m[y][x])

　　for i in range(1,n+1): # count from 1 to n

　　　　if (i) not in col or (i) not in row:

　　　　return False # Fail if integer is missing

　　return True