class Solution {
private:
    struct package{
        public:
            int num;
            int pos;
            //package(int _num,int _pos):this->num(_num),this->pos(_pos){}
            package(int _num,int _pos):num(_num),pos(_pos){}
            
    };
public:
    vector<int> twoSum
 
(vector<int>& nums, int target) {
        vector<int> res;
        int first=0;
        int second=nums.size()-1;
        vector<package> vt;
        for(int i=0;i<nums.size();i++){
            package temp(nums[i],i);
            vt.push_back(temp);
        }
        sort(vt.
 
begin(),vt.end(),[](package p1,package p2)->bool {
            return p1.num<p2.num;
        });
        while(first<=second){
            if(vt[first].num+vt[second].num>target) second--;
            if(vt[first].num+vt[second].num<target) first++;
            if(vt[first].num+vt[second]
 
.num==target){
                res.push_back(vt[first].pos);
                res.push_back(vt[second].pos);
                return res;
            }
        }
    }
};

時間複雜度 O(nlogn+n)