solution.cpp

class Solution
{
public:
    long long dividePlayers(vector<int> &skill)
    {
        // Step 1: Sort the skill array
        sort(skill.begin(), skill.end());

        int n = skill.size();
        int totalSkill = skill[0] + skill[n - 1]; // Required sum for each pair
        long long chemistrySum = 0;

        // Step 2: Pair players using two pointers
        for (int i = 0; i < n / 2; i++)
        {
            // Check if the sum of current pair matches the required totalSkill
            if (skill[i] + skill[n - i - 1] != totalSkill)
            {
                return -1; // Invalid configuration, return -1
            }
            // Calculate the chemistry (product of pair) and add it to the sum
            chemistrySum += (long long)skill[i] * skill[n - i - 1];
        }

        return chemistrySum; // Return total chemistry
    }
};