Question

All,

One of the steps in Swiss pairing algorithm needs to create groups of players having the same score.

E.x.
 P1 - 3
 P2 - 3
 P3 - 2
 P4 - 1
 P5 - 1
 P6 - 1

So this should create 3 groups i.e. 3 arrays consisting Array 1: {P1, P2} ; Array 2: {P3} ; Array 3: {P4, P5, P6}.

This is dynamically changing.

In Java, we could have had an array of arraylist and make it work (One of the solutions I can think of). How can we achieve something like this in PHP?

Answer 1

You can do so as well in PHP with an array:

$array1 = array($P1, $P2);
$array2 = array($P3);
$array3 = array($P4, $P5, $P6);

You might want to stack this into another array as well (grouped by score, probably that’s what you would think of as “arraylist in java”):

$players = array();
foreach(array($P1, ..., $P5) as $player) {
    $score = $player->score;
    $players[$score][] = $player;
}
var_dump($players);

However if the value changes within any of the players group the data must be updated:

class Pairing
{
  private $players;
  public function __construct(array $players) {
    $this->players = $players;
  }
  public function getPairing() {
    $players = array();
    foreach($this->players as $player) {
      $score = $player->score;
      $players[$score][] = $player;
    }
    return $players;
  }
}

$pairing = new Pairing(array($P1, ..., $P5));
...
var_dump($pairing->getPairing());

Or choose the pattern of choice to deal with the events most efficiently.