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2491. Divide Players Into Teams of Equal Skill

Difficulty Topics

Description

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.

Example 2:

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.

Example 3:

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.

 

Constraints:

  • 2 <= skill.length <= 105
  • skill.length is even.
  • 1 <= skill[i] <= 1000

Solution

divide-players-into-teams-of-equal-skill.py
class Solution:
    def dividePlayers(self, skill: List[int]) -> int:
        N = len(skill)
        skill.sort()
        total = sum(skill)

        res = 0
        target = skill[0] + skill[-1]

        for i in range(N // 2):
            a, b = skill[i], skill[-i-1]
            if a + b != target: return -1
            res += a * b

        return res