round-robin.php

<?php

$teams = array('team 1', 'team 2', 'team 3');

if((count($teams) % 2) == 1) {
  array_push($teams, 'bye');
}

$fixed_team = array_slice($teams, 0, 1);
$rotating_teams = array_slice($teams, 1);

$games = array();

//find half minus one offset
$offset = (count($teams)/2)-1;

for($i = 1; $i < count($teams); $i++) {
  //slice the teams for first set and put fixed team at beginning of the first set
  $set_one = array_merge($fixed_team, array_slice($rotating_teams, 0, $offset));
  
  //create second set of teams
  $set_two = array_reverse(array_slice($rotating_teams, $offset));
  
  //create the matchups
  for($j = 0; $j < count($teams)/2; $j++) {
    $games[$i][$j] = array($set_one[$j], $set_two[$j]);
  }
  
  //rotate the teams
  array_unshift($rotating_teams, array_pop($rotating_teams));
}

?>