笔记：udacity计算机科学导论- 课程13/2数独正确性判断

# A list is symmetric if the first row is the same as the first column,

# the second row is the same as the second column and so on. Write a

# procedure, symmetric, which takes a list as input, and returns the
# boolean True if the list is symmetric and False if it is not.

#昨晚数独那题，这一题基本相同，而且，可以减少循环数量。 

def symmetric(o):

    qq = []

    a = 0

    while a < len(o):    

        for p in o:

            if len(p) != len(o):

               return False

            qq.append(p[a])

        if o[a] != qq:                         #o{a]一定不能误写为o(a)

            return False

        a = a + 1

        qq = []

    return True

    # Your code here

#print symmetric([[1, 2, 3],

#                [2, 3, 4],

#                [3, 4, 1]])

#>>> True

print symmetric([["cat", "dog", "fish"],

                ["dog", "dog", "fish"],

                ["fish", "fish", "cat"]])

#>>> True

#print symmetric([["cat", "dog", "fish"],

#                ["dog", "dog", "dog"],

#                ["fish","fish","cat"]])

#>>> False

#print symmetric([[1, 2],

#                [2, 1]])

#>>> True

#print symmetric([[1, 2, 3, 4],

#                [2, 3, 4, 5],