vector<vector<int>> result;
    void func(vector<int> &temp, int index, vector<int> &nums)
    {
        if (index == nums.size())
            result.push_back(temp);
        else
        {
            temp.push_back(nums[index]);
            func(temp, index + 1, nums);
            temp.pop_back();
            while (index + 1 < nums.size() && nums[index] == nums[index + 1])//除重
                index++;
            func(temp, index + 1, nums);
        }
    }
    vector<vector<int>> subsetsWithDup(vector<int>& nums)
    {
        sort(nums.begin(), nums.end());
        if (nums.size() == 0)
            return { {} };
        vector<int> temp;
        func(temp, 0, nums);
        return result;
    }