题解 | #两数之和#

1.hash法

#include<map>

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
        vector<int> res =vector<int>();
        map<int,int> mark = map<int, int>();
        for(int i=0;i<numbers.size();i++) {
            mark[numbers[i]] = i;
        }
        for(int i=0;i<numbers.size();i++) {
            int x = target-numbers[i];
            if(mark.find(x)!=mark.end()&&i!=mark[x]) {
                res.push_back(i+1);
                res.push_back(mark[x]+1);
                return res;
            }
        }
        return res;
    }
};