如何在PHP / MySQL中生成夹具列表？

<?php
$teams = $_GET['t'];
$games = array();   //2D array tracking which week teams will be playing
$weeks = array();   //2D array tracking which teams are playing in a given week

// initialize
for( $i=0; $i<$teams; $i++ ) {
    $games[$i] = array();
    for( $j=0; $j<$teams; $j++ ) {
        if( $i == $j ) { $games[$i][$j] = -1; } //you can't play with yourself ;D
        else { $games[$i][$j] = NULL; }
    }
}

// do the work
for( $w=1,$noblanks=false; !$noblanks; $w++) {
    if( !isset($weeks[$w]) ) { $weeks[$w] = array(); }
    $noblanks = true;   //begin assuming there are no blank spots in the matrix
    for( $i=0; $i<$teams; $i++ ) {
        for( $j=0; $j<$teams; $j++ ) {
            if( $i == $j ) { continue; }    //you can't play with yourself ;D
            if( is_null($games[$i][$j]) ) {
                if( !isset($weeks[$w][$i]) && !isset($weeks[$w][$j]) ) {
                    $games[$i][$j] = $w;    //game between team i and j in week w
                    $weeks[$w][$i] = true;  //mark that team i has game in week w
                    $weeks[$w][$j] = true;  //mark that team j has game in week w
                } else { $noblanks = false; } //this cell is blank,and will be left blank.
            }
        }
    }
}

// display
echo '<pre>';
foreach($games as $row) {
    foreach($row as $col) {
        printf('%4d',is_null($col) ? -2 : $col);
    }
    echo "n";
}
printf("%d teams in %d weeksn",$teams,count($weeks));
echo '</pre>';

样本输出：

-1   1   2   3
   4  -1   3   2
   5   6  -1   1
   6   5   4  -1
4 teams in 6 weeks

  -1   1   2   3   4   5   6
   7  -1   3   2   5   4   8
   8   6  -1   1   7   9   4
   9  10   5  -1   6   7  11
  10   9  11   8  -1   1   2
  11  12  10  13   3  -1  14
  12  13  15  16  17  18  -1
7 teams in 18 weeks

编辑

我已经找到了一种对所有情况都更“周效”的方法,除非团队的数量是2的幂.基本上需要的周数需要2 * number_of_teams.

使用我的’pen-and-paper‘方法,我注意到在矩阵对角线条纹数字非常理想,在我的步行回家中,我想到了一种方法,你可以只输入2个团队ID,并计算团队数量,它会给你回到那个游戏应该发生的那一周.

<?php

function getweek($home,$away,$num_teams) {
    if($home == $away) { return -1; }
    $week = $home+$away-2;
    if( $week > ($num_teams) ) {
        $week = $week-$num_teams;
    }
    if( $home>$away ) {
        $week += $num_teams;
    }
    return $week;
}

$teams = $_GET['t'];
$games = array();   //2D array tracking which week teams will be playing

// do the work
for( $i=1; $i<=$teams; $i++ ) {
    $games[$i] = array();
    for( $j=1; $j<=$teams; $j++ ) {
        $games[$i][$j] = getweek($i,$j,$teams);
    }
}

// display
echo '<pre>';
$max=0;
foreach($games as $row) {
    foreach($row as $col) {
        printf('%4d',is_null($col) ? -2 : $col);
        if( $col > $max ) { $max=$col; }
    }
    echo "n";
}
printf("%d teams in %d weeks,%.2f weeks per teamn",$max,$max/$teams);
echo '</pre>';

示例输出：

-1   1   2   3
   5  -1   3   4
   6   7  -1   1
   7   8   5  -1
4 teams in 8 weeks,2.00 weeks per team

  -1   1   2   3   4   5   6
   8  -1   3   4   5   6   7
   9  10  -1   5   6   7   1
  10  11  12  -1   7   1   2
  11  12  13  14  -1   2   3
  12  13  14   8   9  -1   4
  13  14   8   9  10  11  -1
7 teams in 14 weeks,2.00 weeks per team

编辑(2013年4月)

我修改了getWeek()函数以适用于任意数量的团队.请参阅下面的新功能.约万

function getWeek($home,$num_teams) {
    if($home == $away){
        return -1;
    }
    $week = $home+$away-2;
    if($week >= $num_teams){
        $week = $week-$num_teams+1;
    }
    if($home>$away){
        $week += $num_teams-1;
    }

    return $week;
}