LeetCode 1. 两数之和

题目描述：

解法：

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        unordered_map<int,int> record;
        vector<int> res;
        for(int i=0;i<nums.size();i++){
            if(record.count(nums[i])){
                res.assign({record[nums[i]],i});
            }
            else{
                record[target-nums[i]]=i;
            }
        }
        return res;
    }
};