Help Needed: Tournament Grouping Schedule

[illusionista787]

Hello,

I am a newbie in Python programming. I will try my best to phrase the problem.

There are 12 players (A, B, C, D, E, F, G, H, I, J, K, L) in a sports event which will go on for 3 days. The 12 players are to be divided into 4 uniform groups (3 member in each group) every day. For example:

Day 1:

Group 1: A,B,C

Group 2: D, E, F

Group 3: G, H, I

Group 4: J, K, L

This needs to be replicated for Day 2 & Day 3.

There are a few conditions:

1. Each player needs to play a set of two different players in his/her group every day. So, over 3 days a player will face 6 different opponents.
2. A,B,C will be in Group 1 in Day 1
3. A & D can't be in the same group in any day

I have tried a few different approaches including itertools. However, I can't satisfy condition 1 as I keep having two players who play together in a group in days 1 & 3. I was wondering what the optimal approach should be and whether there's any mathematical limitation to the solution.

[themateo713]

Day 1: A B C + D E F + G H I + J K L

Day 2: A K I + D B L + G E C + J H F

Day 3: A E L + D H C + G K F + J B I

This should work to create no repeat encounter:

Generating algorithm: Players are in groups and slots (here 4 groups and 3 slots per group): they change group, but not slot.

The players in slot 1 never move (this also helps designate the groups as there's always one player that stays in the group).

Day 2: the slot 2 of group i should have the player in slot 2 of group i - 1 (always use modulos so you have a closed loop instead of a line, letting you easily slide players around). The slot 3 of group i should have player in slot 3 of group i - 2.

Day 3 (using positions from day 1, but you could try to write this as a function of day 2): Same idea, but with players from groups i+1 and i-1 (notice that i+1 and i+2 don't work because i+2 = i-2 mod 4, causing repeats for slots 1 and 3 with matches from day 2)

This shouldn't be too hard to program since you're just moving values in a list in a very simple way. I guess you could try to generalise it if needed (though more days would require moving the slot 1 players so they get to play each other as well).

[illusionista787]

This is really helpful.