currently I am actually looking for a term specific for my problem:
I've created a league of >4 Teams The League lasts 3 Rounds (Numbers for the sake of simplicity) Matchups shall be assigned randomly out of Teams a Team has not yet played against.
I am struggling to get my current code running with each fringe case so I'd like to look up 'standard' algorythm developed for such cases, but I cannot come up with the term I am looking for.
One Schedule Example would be:
TeamA: C,E,B
TeamB: F,H,A
TeamC: A,D,H
TeamD: G,C,F
TeamE: H,A,G
TeamF: B,G,D
TeamG: D,F,G
TeamH: E,B,C
I couldn't find anything in that regard, as it seems to be a very, very unlikely thing to be used in leagues/tournaments - however that's my requirement.
This is my current code which creates ONE Round. It may happen, that this code won't give each a team an opponent in round 3 as their possible opponents have a matchup already assigned this round (tested with 6 teams, may occur in Round3)
public function CalculateDivision()
{
$teams = Division::find(1)->teams()->get();
$diffs = array();
foreach($teams as $team)
{
//Get possible Opponents
$opp = Division::find(1)->teams()->where('id','!=',$team->id)->lists('id');
$matches = $team->matches()->get();
$plyd = array();
foreach($matches as $match)
{
//Find Opponents a team already has played against
$plyd[] = $match->teams()->where('id','!=',$team->id)->pluck('id');
}
//Substract Opponents already played against from possible Opponents
$TBP = array_diff($opp,$plyd);
$diffs[$team->id] = $TBP;
}
//Order By Least possible Opponents possible
asort($diffs);
$this->CalculateMatches($diffs);
}
private function CalculateMatches($teams)
{
//$teams equals $teams[teamID] = [Opponent1ID,Opponent2ID ...]
$setTeams = array();
foreach($teams as $key => $team)
{
//If Team hasn't already a new matchup find opponent from their possible opponent array
if(!in_array($key,$setTeams))
{
shuffle($team);
foreach($team as $opponent)
{
//If possible opponent hasn't already a matchup create one, add both teams to 'has already a match' so the loop doesn't evaluate them again
if(!in_array($opponent,$setTeams))
{
$this->CreateMatch($key,$opponent);
$setTeams[] = $key;
$setTeams[] = $opponent;
break;
}
}
}
}
}
Any help for what I shall google would be appreciated
A Swiss system "is a non-eliminating tournament format which features a predetermined number of rounds of competition, but considerably fewer than in a round-robin tournament".
It's widely used in chess and other games. According to Wikipedia:
Swiss systems are commonly used in chess, bridge, eSports, Morabaraba, Scrabble, Backgammon, squash, Pétanque (boules), Quiz bowl, Magic: The Gathering, Policy Debate, Warhammer, eight-ball, Reversi, Dominion, Pokémon TCG, Yu-Gi-Oh, Blood Bowl, Guild Wars 2, Star Wars: X-Wing Miniatures Game, Path of Exile and Android: Netrunner.
It may fit your needs, and you can find some ready-to-use implementation.