力扣C++ 两数之和

 

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        unordered_map<int,int> solu1;
        for (int i = 0; i < nums.size(); i++)
        {
            auto it = solu1.find(target - nums[i]);  //未录，先找
            if(  it!=solu1.end()  )//说明找到了
            {
                return {it->second,i};
            }
            //不管有没有找到，录用
            solu1[nums[i]] = i;
        }
        return {};
    }
};