Generating Unique Groups of 4

So when you say groups of 4 or 5 playing each other, do you mean breaking everyone up into different teams? And do those teams stay constant throughout the tournament? how many teams? how many games?

Originally Posted by Clarkit

Hello,
I'm trying to take a list of 20 people who are participating in a community tournament and breaking them out into unique groups of 4, 5 groups total. The end goal is to have everybody vs each other once (round robin style). We are breaking it into groups so each person knows who they need to play in week 1, week 2, etc..

I'm not clear about what you envision. As I understand this tournament is one-on-one competition. I've got that part completed. With 190 unique pairings I'm confused by what you mean "unique groups of 4, 5 groups total". Unique groups of 4(?) as I envision it would be 47.5 groups. On the other hand 5 groups total would be 5 groups of 38(?).

It would be helpful if you uploaded an Excel file with some hand typed examples of what you envision. Please don't post pictures. Many of us cannot view them (browser limitations, company firewalls, etc.) and it saves having to re-type data. This also answers questions at a glance, and (hopefully) gets you a faster answer.

Thanks.

I no sooner "hung up the phone" on this thread when I got the idea. Once again, brute force and Excel tables came to the rescue. I copied the good team combinations to another table. Then I used the following code to make every possible matchup.

Then I parsed out the team players on the first team, into columns F-I and used ISNUMBER(FIND()) to see if the member was on the other team in Columns J-M. I used NOT(OR(j-M)) to determine which pairings are legitimate.

[Edit] Upon further review, the ruling on the field is overturned. I have duplicates . I'll have to eliminate them the same way as I eliminated duplicate teams.

Please Login or Register  to view this content.

People numbered 1 to 20, 5 rounds of 5 4-player teams:

[ 1 2 3 4 | 5 6 7 8 | 9 10 11 12 | 13 14 15 16 | 17 18 19 20 ]

[ 1 5 9 13 | 2 6 10 17 | 3 7 14 18 | 4 11 15 19 | 8 12 16 20 ]

[ 1 6 15 20 | 2 5 12 18 | 3 9 16 19 | 4 7 10 13 | 8 11 14 17 ]

[ 1 10 16 18 | 2 8 13 19 | 3 5 11 20 | 4 6 9 14 | 7 12 15 17 ]

[ 1 12 14 19 | 2 7 9 20 | 3 8 10 15 | 4 5 16 17 | 6 11 13 18 ]

Results from a family of solutions to the Social Golfer Problem published by Warwick Harvey.