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))