Create and manage a chess tournament.

Two available tournament system:

ROUND-ROBIN SYSTEM :
Rounds
The number of rounds depends on the number of participants, if the number of players is even, the number of rounds is equal to the number of players minus one, otherwise it is equal to the number of players.

Pairings
In the case of a single round-robin tournament the pairings are determined so that each player meets all the other players exactly once during the tournament, in the case of a double round-robin tournament the pairings are determined so that each player meets everyone else exactly twice during the reverse-color tournament.

Score
A win is worth 1 point, a draw is worth 0.5 points for both players and a defeat is worth 0 points.

Sonneborn-Berger Tiebreaker
At the end of the tournament, if two or more players have the same point total, the Sonneborn-Berger tiebreaker is used to determine the winner. A player's Sonneborn-Berger score is calculated by adding the scores of his beaten opponents and half the points scored against the opponents he drew with. This rewards players who defeated stronger opponents during the tournament and helps break ties in the final rankings.

Winner
At the end, the player with the highest total score, including the Sonneborn-Berger score if necessary, is declared the winner of the tournament.

SWISS SYSTEM :
Rounds
The number of rounds depends on the scheduled length of the tournament and the number of participants. Typically, Swiss tournaments last 4 to 9 rounds or more, depending on the circumstances and the total number of participants.

Pairings
On the first round, players are paired randomly. Starting from the second round, players are paired based on their scores accumulated up to that point. The main goals of pairing are to prevent players from meeting more than once, if possible, and to match players with similar scores always trying to alternating colors.

Score
A win is worth 1 point, a draw is worth 0.5 points for both players and a defeat is worth 0 points.

Buchholz Tiebreaker
At the end of the tournament, if two or more players have the same point total, the Buchholz tiebreaker is used to determine the winner. A player's Buchholz score is calculated by adding the scores of his opponents, not considering bye points. This rewards players who defeated stronger opponents during the tournament and helps break ties in the final rankings.

Winner
At the end, the player with the highest total score, including the Sonneborn-Berger score if necessary, is declared the winner of the tournament.