First off, I would like to point out that I am not a student, this is not a homework assignment and I am really not looking for the code per se but for the methodology and perhaps some gotchyas to programming a round robin tournament. This is for a hobby group I chair. Yes, I know the website runs PHP but this is going to be a tool for tournament directors to help them out.

For the last 3 days, I have stared blankly at my computer screen wondering why this should be so hard. For those of you who may not know what a roudn robin tournament is, if there are 4 players in a tournament each player must play 3 games against the remaining players. The kicker and the point *I think* is tripping me up is that obviously the same player can't play two games with different opponents in the same round. Let's say I have 4 players: A, B, C, D.

This is how the rounds would break down (the # of rounds is always $#players)

Round 1
A vs B
C vs D

Round 2
A vs C
B vs D

Round 3
A vs D
B vs C
[download]

Which is easy to program for $#rounds < 6. In fact I got it working quite well. The way I did it was a clever one I thought whereby I just cut the field in half and had the first player play the middle player, second player play the middle player + 1, etc. And then merge the two arrays together then cut it in half and repeat until all rounds were populated. This however will break down in $round >= 6 because the merged array will be the original array and the process starts over again which means that for $players > 7 the players would start playing the same players again. There are no pointers that I could find on the web for round robin tournaments. Plenty for single/double elimination bracket tournaments but round robin seems perhaps to be beyond the scope of normal Japhies.

Help is greatly appreciated.

20031022 Edit by castaway: Changed title from 'Please Save My Withering Hair!'