2491. Divide Players Into Teams of Equal Skill

class Solution {
public:
    long long dividePlayers(vector<int>& skill) {
        int i = 0, j = skill.size()-1;

        sort(skill.begin(), skill.end());

        long long ans = 0;
        int sum = 0;

        sum = skill[i] + skill[j];
        ans += (skill[i] * skill[j]);
        i++;
        j--;

        while(i < j)
        {
            int temp = skill[i] + skill[j];

            if(temp == sum)
            {
                ans += (skill[i] * skill[j]);
            }
            else 
            {
                return -1;
            }
            i++;
            j--;
        }
        return ans;
    }
};