README.md

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 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

Solutions (Rust)

1. Solution

impl Solution {
    pub fn divide_players(skill: Vec<i32>) -> i64 {
        let n = skill.len();
        let mut skill = skill;
        let mut ret = 0;

        skill.sort_unstable();

        for i in 0..n / 2 {
            if skill[i] + skill[n - 1 - i] != skill[0] + skill[n - 1] {
                return -1;
            }

            ret += skill[i] as i64 * skill[n - 1 - i] as i64;
        }

        ret
    }
}