Divide Players Into Teams of Equal Skill.py

'''
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 players into teams such that the total skill of each team is equal.

Example 1:

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.
'''

class Solution(object):
    def dividePlayers(self, skill):
        """
        :type skill: List[int]
        :rtype: int
        """
        skill.sort()
        i=0
        j=len(skill)-1
        ans=0
        x=skill[0]+skill[-1]
        while(i<j):
            if skill[i]+skill[j]==x:
                ans+=skill[i]*skill[j]
                i+=1
                j-=1
            else:
                return -1
        return ans