<?php
/***********************
* 作者:大龄青年(QQ:303015292)
* 主页:http://blog.csdn.net/hahawen
* 功能:用php计算24点游戏 
************************/
set_time_limit(0);
$values = array(1, 5, 5, 5);
$result = 24;
$list = array();

echo "<pre>";
makeValue($values);
print_r($list);
function makeValue($values, $set=array())
{
$words = array("+", "-", "*", "/");
if(sizeof($values)==1)
{
  $set[] = array_shift($values);
  return makeSpecial($set);
}
foreach($values as $key=>$value)
{
  $tmpValues = $values;
  unset($tmpValues[$key]);
  foreach($words as $word)
  {
   makeValue($tmpValues, array_merge($set, array($value, $word)));
  }
}
} 

function makeSpecial($set)
{
$size = sizeof($set);
if($size<=3 || !in_array("/", $set) && !in_array("*", $set))
{
  return makeResult($set);
}
for($len=3; $len<$size-1; $len+=2)
{
  for($start=0; $start<$size-1; $start+=2)
  {
   if(!($set[$start-1]=="*" || $set[$start-1]=="/" || $set[$start+$len]=="*" || $set[$start+$len]=="/"))
   continue;
   $subSet = array_slice($set, $start, $len);
   if(!in_array("+", $subSet) && !in_array("-", $subSet))
   continue;
   $tmpSet = $set;
   array_splice($tmpSet, $start, $len-1);
   $tmpSet[$start] = "(".implode("", $subSet).")";
   makeSpecial($tmpSet); 
  }
}
} 

function makeResult($set)
{
global $result, $list;
$str = implode("", $set);
@eval("$num=$str;");
if($num==$result && !in_array($str, $list))
$list[] = $str;
} 

?>