PHP实现的简单排列组合算法应用示例

本文实例讲述了PHP实现的简单排列组合算法应用。分享给大家供大家参考，具体如下：

一、问题：

给你一个40斤的西瓜，给3个人分，有多少种分法？

二、PHP实现代码：

<?php$aa = range(1,40);$bb = array();foreach($aa as $k=>$val){  foreach($aa as $v){    foreach($aa as $vl){      $sum = $val+$v+$vl;      if($sum == 40){        $bb[$k][0] = $val;        $bb[$k][1] = $v;        $bb[$k][2] = $vl;      }    }  }}echo '<pre>';print_r($bb);exit;?>

运行结果如下：

Array(  [0] => Array    (      [0] => 1      [1] => 38      [2] => 1    )  [1] => Array    (      [0] => 2      [1] => 37      [2] => 1    )  [2] => Array    (      [0] => 3      [1] => 36      [2] => 1    )  [3] => Array    (      [0] => 4      [1] => 35      [2] => 1    )  [4] => Array    (      [0] => 5      [1] => 34      [2] => 1    )  [5] => Array    (      [0] => 6      [1] => 33      [2] => 1    )  [6] => Array    (      [0] => 7      [1] => 32      [2] => 1    )  [7] => Array    (      [0] => 8      [1] => 31      [2] => 1    )  [8] => Array    (      [0] => 9      [1] => 30      [2] => 1    )  [9] => Array    (      [0] => 10      [1] => 29      [2] => 1    )  [10] => Array    (      [0] => 11      [1] => 28      [2] => 1    )  [11] => Array    (      [0] => 12      [1] => 27      [2] => 1    )  [12] => Array    (      [0] => 13      [1] => 26      [2] => 1    )  [13] => Array    (      [0] => 14      [1] => 25      [2] => 1    )  [14] => Array    (      [0] => 15      [1] => 24      [2] => 1    )  [15] => Array    (      [0] => 16      [1] => 23      [2] => 1    )  [16] => Array    (      [0] => 17      [1] => 22      [2] => 1    )  [17] => Array    (      [0] => 18      [1] => 21      [2] => 1    )  [18] => Array    (      [0] => 19      [1] => 20      [2] => 1    )  [19] => Array    (      [0] => 20      [1] => 19      [2] => 1    )  [20] => Array    (      [0] => 21      [1] => 18      [2] => 1    )  [21] => Array    (      [0] => 22      [1] => 17      [2] => 1    )  [22] => Array    (      [0] => 23      [1] => 16      [2] => 1    )  [23] => Array    (      [0] => 24      [1] => 15      [2] => 1    )  [24] => Array    (      [0] => 25      [1] => 14      [2] => 1    )  [25] => Array    (      [0] => 26      [1] => 13      [2] => 1    )  [26] => Array    (      [0] => 27      [1] => 12      [2] => 1    )  [27] => Array    (      [0] => 28      [1] => 11      [2] => 1    )  [28] => Array    (      [0] => 29      [1] => 10      [2] => 1    )  [29] => Array    (      [0] => 30      [1] => 9      [2] => 1    )  [30] => Array    (      [0] => 31      [1] => 8      [2] => 1    )  [31] => Array    (      [0] => 32      [1] => 7      [2] => 1    )  [32] => Array    (      [0] => 33      [1] => 6      [2] => 1    )  [33] => Array    (      [0] => 34      [1] => 5      [2] => 1    )  [34] => Array    (      [0] => 35      [1] => 4      [2] => 1    )  [35] => Array    (      [0] => 36      [1] => 3      [2] => 1    )  [36] => Array    (      [0] => 37      [1] => 2      [2] => 1    )  [37] => Array    (      [0] => 38      [1] => 1      [2] => 1    ))