1688. Count of Matches in Tournament

package LeetCode_1688

/**
 * 1688. Count of Matches in Tournament
https://leetcode.com/problems/count-of-matches-in-tournament/

You are given an integer n, the number of teams in a tournament that has strange rules:
1. If the current number of teams is even, each team gets paired with another team.
    A total of n / 2 matches are played, and n / 2 teams advance to the next round.
2. If the current number of teams is odd, one team randomly advances in the tournament, and the rest gets paired.
    A total of (n - 1) / 2 matches are played, and (n - 1) / 2 + 1 teams advance to the next round.
Return the number of matches played in the tournament until a winner is decided.
 * */
class Solution {
    /*
    * solution: follow by rules, Time:O(logn), Space:O(1)
    * */
    fun numberOfMatches(n_: Int): Int {
        var n = n_
        var matches = 0
        while (n != 1) {
            if (n % 2 == 0) {
                n /= 2
                matches += n
            } else {
                n = (n - 1) / 2
                matches += n
                n += 1
            }
        }
        return matches
    }
}