Double round robin: each team plays two games with other teams. All participating teams can meet twice, and finally rank according to the points and gains and losses of each team in all competitions in the two periods.
Generally speaking, there are not many single round robin matches for the participating teams, and there is enough time for them to use.
If there are few teams or more competition opportunities, double-cycle competition is usually adopted.
For example, the national men's basketball League A adopts the home and away game system, and in the first stage of the preliminaries and the 9~ 12 relegation match, the double round robin system is adopted.
Extended data:
1, the calculation of single cycle game
The calculation formula is: X=N(N- 1)/2, that is, the number of people in line * (the number of people in line-1)/2. For example, 8 teams participate in the competition, and the total number of games is: [8x(8- 1)]/2=28 games.
Generally, the arrangement of single-cycle competition sequence adopts rotation method. No matter whether the teams are even or odd, they should be ranked even. If it is an odd number, you can add a "0", and the team that meets a "0" will have a bye.
2. Calculation of double-cycle game.
If there are n teams, the number of matches is N(N- 1). For example, 7 teams, the total number of games: 7*(7- 1)=42 games.
The number of rounds, the number of games and the competition time of double round robin are all multiples of single round robin.
Baidu encyclopedia-single round robin system
Baidu Encyclopedia-Double Cycle System