90.Subsets II

思路:

• 和Subsets类似，因为数组中有重复元素，所以用set存储结果，相当于正常遍历然后去掉了重复。

class Solution {
public:
    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        sort(begin(nums),end(nums));
        vector<vector<int>>re;
        set<vector<int>>res;
        vector<int>tmp;
        dfs(nums,res,0,tmp);
        copy(res.begin(),res.end(),back_inserter(re));  //
        return re;
    }
    void dfs(vector<int>& nums,set<vector<int>>& res,int i,vector<int>& tmp){
        if(i == nums.size()){
            res.insert(tmp);
            return ;
        }
        for(int j = 0; j < 2; j++){
            if(j == 0){
                dfs(nums,res,i+1,tmp);
            }else{
                tmp.push_back(nums[i]);
                dfs(nums,res,i+1,tmp);
                tmp.pop_back();
            }
        }
    }
};