2491. Divide Players Into Teams of Equal Skill

You are given a positive integer array skill of even length n where skill[i] denotes the skill of the ith player. Divide the players into n / 2 teams of size 2 such that the total skill of each team is equal. The chemistry of a team is equal to the product of the skills of the players on that team. Return the sum of the chemistry of all the teams, or return -1 if there is no way to divide the pl