Round Robin Tournament Scheduling
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8 teams, 9 events, each team plays each event once

cab11983 · 3 · 4911
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cab11983

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on: November 27, 2015, 03:53:14 PM
I'm doing Beer Olympics tomorrow.  ;D ;D ;D
There is 8 teams with 9 events. I need every team to play each event only ONCE. Help!? Yes, I know each team is going to end up playing 2 teams they already played but in a different event. I tried round robin schedule makers online but none of them worked. Thanks for your help!

You can name teams 1-8
Events are Beer pong, Lifesize beer pong, Kan Jam, Beerball, Beerbee, Cornhole, Dizzy bat, Chug-A-Lug, and Flip Cup

If possible, can you post possibilites of7, 8, 9, and 10 teams in case more or less people show up?

Thanks!

Ian Wakeling

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Reply #1 on: November 28, 2015, 03:33:23 AM
The only scenario from your list that I can produce quickly is 10 teams - it is also the most balanced option as all teams play each other exactly once.  For example:

( 2  5) ( 6  8) (-----) (-----) (-----) ( 1  3) (10  9) ( 7  4) (-----)
( 6  3) (-----) ( 9  4) (-----) ( 5  1) ( 7  8) (-----) ( 2 10) (-----)
(-----) ( 9  2) ( 8  5) (10  3) ( 4  6) (-----) (-----) (-----) ( 7  1)
(-----) ( 1 10) (-----) ( 7  6) ( 3  2) (-----) ( 8  4) (-----) ( 9  5)
( 4  1) (-----) ( 7  3) (-----) ( 8  9) ( 5 10) (-----) (-----) ( 2  6)
(-----) ( 7  5) (-----) ( 8  2) (-----) (-----) ( 6  1) ( 3  9) (10  4)
(10  8) ( 3  4) (-----) ( 1  9) (-----) (-----) ( 7  2) ( 5  6) (-----)
( 7  9) (-----) ( 6 10) (-----) (-----) ( 4  2) ( 5  3) ( 1  8) (-----)
(-----) (-----) ( 2  1) ( 4  5) ( 7 10) ( 9  6) (-----) (-----) ( 3  8)


It's symmetric, so rows and columns can be assigned to rounds/events either way around.  If you were to have only 8 teams then I would recommend dropping two rounds/events and playing the similar 7x7 square below:

(---) (7 3) (5 1) (---) (6 4) (2 8) (---)
(---) (6 8) (---) (7 2) (---) (3 1) (4 5)
(---) (---) (2 4) (5 3) (1 8) (---) (6 7)
(3 4) (---) (8 7) (---) (---) (6 5) (1 2)
(6 2) (1 4) (---) (---) (5 7) (---) (8 3)
(8 5) (---) (---) (6 1) (3 2) (4 7) (---)
(7 1) (2 5) (6 3) (4 8) (---) (---) (---)


Hope that helps.
« Last Edit: November 28, 2015, 03:34:44 AM by Ian »

Ian Wakeling

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Reply #2 on: November 28, 2015, 03:48:29 AM
An afterthought.  If you do have 9 or 7 teams then I would use the same schedules above but remove the games involving the highest numbered team.  This will leave you with a schedule where teams play at all but one of the events - this is the best you can do, if you do not wish to violate your 'events only once' criterion.

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