src.cpp

#include <map>
#include <vector>
#include <cstdio>
#include <cstdlib>
using namespace std;
class Solution {
public:
    vector<int> twoSum(vector<int> &numbers, int target) {
		map<int, int> m;
		vector<int> result;
		for (size_t i = 0; i < numbers.size(); ++i) {
			if (m.find(numbers[i]) == m.end()) {
				m[target - numbers[i]] = i;
			} else {
				result.push_back(m[numbers[i]] + 1); // index from 1, not 0
				result.push_back(i + 1); // index from 1
			}
		}
		return result;
    }
};
int main(int argc, char **argv)
{
	Solution solution;
	vector<int> numbers = {2,7,11,15};
	auto result = solution.twoSum(numbers, 9);
	printf("%d\n%d\n", result[0], result[1]);
	return 0;
}