剑指Offer_编程题27：字符串的排列

题目：输入一个字符串,按字典序打印出该字符串中字符的所有排列。例如输入字符串abc,则打印出由字符a,b,c所能排列出来的所有字符串abc,acb,bac,bca,cab和cba。

我只能说自己递归的学的不好。。。。。。大概能看懂吧。。。。。。。

# -*- coding:utf-8 -*-
class Solution:
    def Permutation(self, ss):
        # write code here
        if not len(ss):
            return []
        if len(ss) == 1:
            return list(ss)

        charList = list(ss)
        charList.sort()
        pStr = []
        for i in range(len(charList)):
            if i > 0 and charList[i] == charList[i-1]:
                continue
            temp = self.Permutation(''.join(charList[:i])+''.join(charList[i+1:]))
            for j in temp:
                pStr.append(charList[i]+j)
        # 返回值 其他时刻返回的temp
        return pStr

if __name__ == '__main__':
    abc = Solution()
    w = abc.Permutation('aa')
    print(w)