count-of-matches-in-tournament_1688.py

# You are given an integer n, the number of teams in a tournament that has strange rules:

# 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.
# 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.


# Example 1:

# Input: n = 7
# Output: 6
# Explanation: Details of the tournament:
# - 1st Round: Teams = 7, Matches = 3, and 4 teams advance.
# - 2nd Round: Teams = 4, Matches = 2, and 2 teams advance.
# - 3rd Round: Teams = 2, Matches = 1, and 1 team is declared the winner.
# Total number of matches = 3 + 2 + 1 = 6.
# Example 2:

# Input: n = 14
# Output: 13
# Explanation: Details of the tournament:
# - 1st Round: Teams = 14, Matches = 7, and 7 teams advance.
# - 2nd Round: Teams = 7, Matches = 3, and 4 teams advance.
# - 3rd Round: Teams = 4, Matches = 2, and 2 teams advance.
# - 4th Round: Teams = 2, Matches = 1, and 1 team is declared the winner.
# Total number of matches = 7 + 3 + 2 + 1 = 13.

# ---------------------------------------Runtime 39 ms Beats 44.26% Memory 16.3 MB Beats 35.39%---------------------------------------


class Solution:
    def numberOfMatches(self, n: int) -> int:
        total = matches = 0
        while n > 1:
            odds_or_even = n % 2 == 0
            if odds_or_even:
                total = n // 2
                n = n - total
            else:
                total = (n - 1) // 2
                n = (n - 1) // 2 + 1

            matches += total
        return matches