You are given a positive integer array
skill of even length
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 players into teams such that the total skill of each team is equal.
Input: skill = [3,2,5,1,3,4] Output: 22 Explanation: Divide the players into the following teams: (1, 5), (2, 4), (3, 3), where each team has a total skill of 6. The sum of the chemistry of all the teams is: 1 * 5 + 2 * 4 + 3 * 3 = 5 + 8 + 9 = 22.
Input: skill = [3,4] Output: 12 Explanation: The two players form a team with a total skill of 7. The chemistry of the team is 3 * 4 = 12.
Input: skill = [1,1,2,3] Output: -1 Explanation: There is no way to divide the players into teams such that the total skill of each team is equal.
2 <= skill.length <= 105
1 <= skill[i] <= 1000