该怎么完善这个代码？

#include <iostream>
#include <vector>
#include <map>
#include <set>
using namespace std;
class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) 
    {
        unordered_map<int, int> hashtable;
        for (int i = 0; i < nums.size(); ++i)
         {
            auto it = hashtable.find(target - nums[i]);
            if (it != hashtable.end()) 
            {
                return {it->second, i};
            }
            hashtable[nums[i]] = i;
        }
        return {};
    }
};
int main()
{

    return 0;
}

#include <iostream>
#include <vector>
#include <unordered_map>

using namespace std;

class Solution
{
public:
    vector<int> twoSum(vector<int> &nums, int target)
    {
        unordered_map<int, int> hashtable;
        for (int i = 0; i < (int)nums.size(); ++i)
        {
            auto it = hashtable.find(target - nums[i]);
            if (it != hashtable.end())
            {
                return {it->second, i};
            }
            hashtable[nums[i]] = i;
        }
        return {};
    }
};

int main()
{
    vector<int> nums{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    vector<int> r = Solution().twoSum(nums, 5);
    if (!r.empty())
        cout << r[0] << ' ' << r[1] << endl;
    return 0;
}