Single Round Robin

Source: Internet
Author: User

A single cycle means that all teams can meet each other once in the competition, and finally rank each other based on the number of scores in the competition and the number of winning or losing matches. A single cycle is usually used only when there are not many teams in the competition and there is enough competition time. The single cycle is a fair and reasonable competition system because all teams participating in the competition have the opportunity to compete.
I. Calculation of the number of rounds and number of games in a single loop
(1) number of rounds: In a round-robin competition, all teams have completed one round of competition.
When the number of participating teams is singular, the number of rounds equals to the number of teams. If five teams participate in the competition, the number of rounds is five.
When the number of teams participating in the competition is double, the number of rounds equals to the number of teams minus one. If six teams participate in the competition, the number of rounds is five.
② Number of matches: the number of matches in a single loop can be calculated using the following formula (simple mathematical combination formula ):
Number of matches = number of teams * (number of teams-1)/2
If 6 or 7 teams participate in the competition, the number of matches is:
6*(6-1)/2 = 15 (field) 7*(7-1)/2 = 21 (field)
2) orchestration competition round table
The team is organized by an even number regardless of the odd or even number. If the number of teams is odd, add "0" at the end of the number to make it an even number. The team is empty when it hits 0. During the orchestration, the teams are evenly divided into half of the left and right sides. The number of the left half is arranged from top to bottom in order of serial number 1, and the number of the right half is arranged from bottom to top in order of numbers, then it is connected by a horizontal line to form the first round of the competition. Since the second round, there are multiple rotation methods.
There are two common types:
(1) fixed rotation orchestration Method
The fixed rotation method is also called the conventional rotation method, which is a traditional arrangement method in China. Table 17-6 is the 7 teams participating in the round table, which is fixed on the first on the left side, clockwise, and discharged one by one.
As shown in the table:

(2) "bergel" orchestration Method
Since 1985, most international competitions have adopted the "berger" orchestration method. The advantage is that when the singular team participates, it can avoid unreasonable competition between the empty team in the second round and the previous round from the fourth round.
Using the "berger" orchestration method, if the chorus is a double number, the chorus is divided into half (when the chorus is a singular number, the "0" is used to form a double number ), the first half starts from the first half, and is written from the top to the left; the second half is written from the top to the right, and then connected by a horizontal line. This is the first round of competition.
In the second round, move the number ("0" or the largest number of codes) in the upper right corner of the first round to the upper left corner, three rounds to the upper right corner, and so on.
That is to say, "0" or the largest code is in the upper right corner of the singular round, while "Double Round" is in the upper left corner. As follows:
Orchestration Method for 7 teams
The first round, the second round, the third round, the fourth round, the fifth round, the sixth round, and the seventh round
1-0 0-5 2-0 0-6 3-0 0-7 4-0
2-7 6-4 3-1 7-5 4-2 1-6 5-3
3-6 7-3 4-7 1-4 5-1 2-5 6-2
4-5 1-2 5-6 2-3 6-7 3-4 7-1
Whether the game team is a singular or double number, in the last round, it must be "0" or the largest code in the upper right corner, "1" in the lower right corner.
According to the number of different teams, when "1" moves a position counterclockwise, it should move according to the specified number of intervals (see table ), "0" or the maximum number of codes should move before "1.
Interval Movement
Number of teams
Less than 4 teams 0
5 ~ 6 teams 1
7 ~ 8 teams 2
9 ~ 10 teams 3
11 ~ 12 teams 4
When "1" is used for Interval movement, when "0" or the maximum number of codes is used, it should be crossed first.
Generally, in domestic competitions, the names and times obtained by each team in the above competitions are used as codes, such as 1st for "1" and 2nd for "2. In most world competitions, the host code is "1", and the last 1st is "2. Some games also use the lottery method to determine the code.
For example

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