题解 | #两数之和#哈希表用来快速查找时间复杂度O(n)

class Solution {
public:
    /**
     * 
     * @param numbers int整型vector 
     * @param target int整型 
     * @return int整型vector
     */
    vector<int> twoSum(vector<int>& numbers, int target) {
        // write code here
        unordered_map<int,int> mp;
        int n = numbers.size();
        for(int i = 0; i < n; i++)
        {
            if(mp.count(target-numbers[i]))
            {
                return {mp[target-numbers[i]],i+1};
            }
            mp[numbers[i]] = i+1;            
        }
        return {};
            
    }
};