The round robin system includes three ways: single cycle, double cycle and grouping cycle.
single loop
Single cycle means that all participating teams can meet once, and finally rank according to the points and gains and losses of each team in all competitions. If there are not many teams and the time and venue are guaranteed, this kind of competition is usually adopted.
Calculation of the number of rounds in a single round-robin competition
If the number of teams is even, the number of rounds is the number of teams minus 1.
For example, if 8 teams participate in the competition, the number of rounds is 8- 1=7.
If the number of teams is odd, the number of rounds is equal to the number of teams.
For example, if five teams participate in the competition, it will take five rounds.
The purpose of calculating the number of rounds is to calculate the total time required for the game.
For example, there are seven participants in the competition, and the number of rounds is seven. If there is a two-day break in the middle of the game, the total time of the game is nine days.
Calculation of the number of single-cycle games
The formula for calculating the number of players in a single round-robin game is: x = n (n-1 )/2, that is, the number of players * (the number of players-1 )/2.
For example, 8 teams participate in the competition, and the total number of competitions is:
The purpose of calculating the number of games is to calculate the number of venues needed for the game, and then consider the number of referees and how to arrange the game schedule.
Arrangement of single round robin
Generally, the arrangement of single-cycle competition sequence adopts rotation method.
No matter whether the number of teams is even or odd, they should be arranged in even numbers. If it is an odd number, you can add a "0", and the team that meets a "0" will have a bye.
For example, there are 8 teams participating in the competition, as shown in table 1- 1. Chart display
This rotation method is suitable for teams that don't know each other's strength, so it is very likely that the strong teams will meet in advance by drawing lots and positioning.
Counter-clockwise rotation can keep the final game exciting, which is the usual arrangement method (Table 1-2). Chart display
When there are five teams participating in the competition, they can be arranged by adding "0", as shown in Table 1-3. Chart display
The following methods can usually keep the final competition exciting, which are common arrangement methods, as shown in Table 1-4. Chart display
In order to avoid uneven work and rest, you can also put "0" in the lowest position on the far right and keep it still.
After the round-table meeting is arranged, each team draws lots, fills in the round-table meeting according to the number drawn by each team (or determines the number according to the ranking order of the last game), and then prepares the competition schedule. When compiling the competition schedule, we should first implement the principle of equal opportunity and fair competition, and of course, we should also take care of the needs of the competition (audience) appropriately. We can adjust the time (morning, afternoon, evening), venue (large or small pavilion), region (local or foreign) and other aspects to achieve a general balance between teams.
In the arrangement, the interval between rounds should be considered to ensure that athletes have enough rest time. If the competition cycle allows, you usually have to take a day off after three rounds. The color of the clothes should be implemented according to the rules, that is, the top team (home team) of the squadron in the order book should wear dark clothes. Pay attention to leaving time for washing and drying when finishing.
Table 1-5 is a more formal competition schedule format. Chart display
Domestic and international circulation
Double cycle means that all teams can meet twice, and finally rank according to the points and gain and loss rates of all teams in the two cycles. If there are few teams or more competition opportunities, double-cycle competition is usually adopted.
At present, the national men's basketball League A adopts the home and away game system, and the first stage of the preliminaries and the 9~ 12 relegation game adopt the double round robin system.
The number of rounds, the number of games and the competition time of double round robin are all multiples of single round robin.
Grouping period
The grouping cycle is to divide all the participating teams into several groups for the first-stage preliminary contest, and then for the second-stage finals between the winning teams in each group, so as to determine the ranking below 1. In the group preliminaries, the single round robin system can be adopted, and in the finals, the single round robin system, the second namesake competition and the cross competition system can be adopted, so it is also called the mixed round robin system or the two-stage system. Group cycle is suitable for competitions with many teams, and it can complete the competition tasks reasonably and fairly in a short time.
The disadvantage of grouping cycle is that the participating teams >>
Question 2: Double Cycle Double Cycle Tournament 20 1 1 Women's League no longer implements the competition system, but adopts the double cycle sub-station competition system. The competition system spans seven months, and the number of league matches of each team will increase to 30. Together with this year's FA Cup and National Championships, each player will play about 40 games, while all the games in the past year were 15 to 25. Double-round-robin race system means that the league is divided into 10 stations for double-round-robin races throughout the year. Each station has four divisions and each division has four teams. The final competition ranking is arranged according to the total points of each substation throughout the year. All member associations and clubs have adopted the competition system. Previously, the China Football Association had considered adopting the home and away double round robin system, but considering the scientific distribution of the amount of training matches for women's football players and the limitation of funds, it finally adopted the form of divided matches.
Question 3: If Team N plays double round robin, the formula of the number of matches is (n- 1)*2.
Question 4: What does the single round robin mean? How to calculate the number of matches for each team? Single round robin refers to a match between team A and team B, and the loser is eliminated directly, which is the opposite of double round robin. The double round robin is that A plays one game at home and B plays one game at home. Finally, if A wins both games, A will be promoted. One win and one loss depends on the number of goals scored.
Question 5: There are 10 basketball teams, and the number of games to be played is [9+8+7+6+5+4+3+2+1] × 2 = 90.
Question 6: The single cycle and double cycle of a football match are two games. For example, there are 20 teams in a league, so their league is usually a single cycle. That is, any two teams have to play twice. 20 teams will have 38 rounds (20 minus 1 then 2 because they can't beat themselves). Generally, European leagues are single-cycle, that is, home and away games are played once, but there are exceptions. For example, in the Scottish League, they only have 10 teams, so they have to play a double round robin game, that is, different teams have to play four times, two at home and two away games each time. For example, the team with 10 is 36 rounds (10 minus 1 multiplied by 4).
Question 7: Six teams play double round robin. How many rounds does a * * * have to play? The factorial of permutation combination 6 is 120 fields.