Group Games

Shocker

Well, I have a problem.

I need to program a tournament or league, where I have a group of players, and I have to calculate the games, until each players has played against every other player.
To find all games, which have to be played is not the problem, the problem is that every player can only play once in a round. Let's say we have 4 players in a group, so there are 3 rounds with 2 games each.

How can I bring the games in the right order?

drawmack

This code is untested so you'll have to debug it.

<?php
/*array*/ function games(&$players) {
    //make sure we have multiple players
    if(!is_array($players)) {return FALSE;}

//make sure we have an even number of players
if((count($players) -1)%2 != 0) {return FALSE;}

   $games = array();

//create the games
for($i=0;$i<count($players);$i = $i+2) {
    $games[] = array($players[$i],$players[$i+1]);
} //end for

return $games;
} //end games

$players = array('joe','bill','bob','jane');
$games = games($players);
for($i=0;$i<count($games);$i++) {
    echo "GAME " . $i . ": " .  $games[$i][0] . " vs. " . $games[$i][1] . "<br />\n";
} //end for
?>

Shocker

Hm, thanks for your effort, but the code is useless...

It just creates the following games:
1:2
3:4

But I need these:
1:2
3:4

1:3
2:4

1:4
2:3

(3 rounds)

drawmack

You assert that the code is useless, I assert it just needs a little modifycation:

(again untested)

<?php
/*array*/ function games(&$players) {
    //make sure we have multiple players
    if(!is_array($players)) {return FALSE;}

//make sure we have an even number of players
if((count($players) -1)%2 != 0) {return FALSE;}

   $games = array();

//create the games
for($i=0;$i<(count($players)-1);$i++ = $i+2) {
    for($j=$i+1;$j<count($players);$j++) {
        $games[] = array($players[$i],$players[$j]);
    } //end for j
} //end for i

return $games;
} //end games

$players = array('joe','bill','bob','jane');
$games = games($players);
for($i=0;$i<count($games);$i++) {
    echo "GAME " . $i . ": " .  $games[$i][0] . " vs. " . $games[$i][1] . "<br />\n";
} //end for
?>

[/B][/QUOTE]

Shocker

Thanks again, but I already mentioned in my first post, that the order of the games is important.
With 4 players, I have 3 rounds, 2 games each round. Agree?
No I can't say, the first game is 1:2 and the second game is 1:3, because player 1 can't play twice in one round.

Sorry if I have not explained my problem well enough.

drawmack

okay, and what I've provded you with is a function that gives you an array that looks like this
1:2, 1:3, 1:4, 2:3, 2:4, 3:4

let's call that $a

there are four players, so you'll have 2 (or 4/2) games per round and 3 (or 4-1) rounds made up of games
$a[0] and $a[0 + (4-1)]
$a[1] and $a[1 + (4-1)]
$a[2] and $a[2 + (4-1)]

okay, now let's say there are six players, you'll have an array that looks like this:
1:2, 1:3, 1:4, 1:5, 1:6, 2:3, 2:4, 2:5, 2:6, 3:4, 3:5, 3:6, 4:5, 4:6, 5:6

let's call that $b

Now each round has 3 (or 6/2) games per round and 5 (or 6-1) rounds.

It's trivial array manipulation and if you're not at least willing to give it a shot then I"m not willing to help anymore.

Shocker

Thanks, that looks promising. 🙂
Unfortunately the system won't work. From your state of view, I should use the mathes 0 and 3 for the first round, but then the player 2 plays double...

And I cannot use the system if I have 6 players.. 🙁