078 Subsets

class Solution:
    # @param {integer[]} nums
    # @return {integer[][]}
    def subsets(self, nums):
        nums.sort()
        return self.help(nums, 0)

    def help(self, nums, s):
        ans = []
        if s == len(nums) - 1:
            return [[],[nums[-1]]]
        for se in self.help(nums, s+1):
            ans.append(se)
            tmp = [nums[s]]
            tmp.extend(se)
            ans.append(tmp)
        return ans