以下解决方案有效,但我认为对于不是 2 的幂的团队数量来说,它不能尽可能高效地完成日程安排。此外,对于所有情况,代码的效率都是 n^2 [可能是 n^3?],所以我希望你不需要一次安排超过几百个团队。:P
<?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 weeks\n", $teams, count($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“高效”的方法,除非团队数量是 2 的幂。基本上需要的周数变为2 * number_of_teams
.
使用我的“纸笔”方法,我注意到在矩阵上沿对角线排列数字非常理想,在回家的路上,我想到了一种方法,您可以只输入 2 个团队 ID,以及团队数量和它会让你回到那场比赛应该举行的那一周。
<?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 team\n", $teams, $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)
我已经修改了该getWeek()
功能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, $away, $num_teams) {
if($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;
}