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by Sumit Chourasia | Dec 28, 2020 | Category :coding | Tags : algorithm data-structure easy leetcode string

Count of Matches in Tournament - String - Easy - LeetCode

Count of Matches in Tournament - String - Easy - LeetCode

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.
 

Constraints:

1 <= n <= 200

public class Solution {
    public int NumberOfMatches(int n) {
        int total = 0;
        while(n>1){
            total+=n/2;            
            if(n%2!=0 && n != 1){
                n++;
            }
            n=n/2;
        }
        
        return total;
    }
}

Time Complexity: O(logn)

Space Complexity: O(1)