#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))