LeetCode90

class Solution {

public:

    vector>res;

    vectortemp;

    vector> subsetsWithDup(vector& nums) {

        sort(nums.begin(),nums.end());

        backtracking(nums,0);

        return res;

    }

    void backtracking(vector&nums,int st)

    {

        if(temp.size()<=nums.size())

        {

            res.push_back(temp);

        }

        else

            return;

        for(int i=st;i

        {

                //下面两行代码是精髓，用来去除重复

            if(i>st&&nums[i]==nums[i-1])

                continue;

            temp.push_back(nums[i]);

            backtracking(nums,i+1);

            temp.pop_back();

        }

    }

};