#Leet Code# Permutation

描述：

输出全排列

代码：

 class Solution:
     # @param num, a list of integer
     # @return a list of lists of integers
     def doSth(self, num):
         result = self.permute(num[1:])
         for lst in result:
             for i in range(len(lst) + 1):
                 yield lst[:i] + num[:1] + lst[i:]

     def permute(self, num):
         if len(num) == 0: return []
         if len(num) == 1: return [num]

         return list(self.doSth(num))