90. 子集 II

//套模板
class Solution 
{
    vector<vector<int>> res;
    void helper(vector<int>& nums, int start, vector<int>& out)
    {
        res.push_back(out);
        for (int i = start; i < nums.size(); ++i)
        {
            if(i != start && nums[i] == nums[i - 1]) continue;//去重

            out.push_back(nums[i]);
            helper(nums, i + 1, out);
            out.pop_back();
        }
    }
public:
    vector<vector<int>> subsetsWithDup(vector<int>& nums) 
    {
        vector<int> out;
        sort(nums.begin(),nums.end());//排序
        helper(nums,0,out);
        //去重
        // sort(res.begin(),res.end());
        // auto it = unique(res.begin(),res.end());
        // res.erase(it,res.end());

        return res;
    }
};