A powerful PHP program for computing 24-point games

The PHP program of a powerful 24-point game has been used for 24-point games. how can we use a program to calculate the random combination of 4 numbers to get the result of 24? For example, for the numbers 5, 5, 5, and 1, how can we get the result 24? The following describes a very powerful program that can list all the combinations that meet the conditions.

 "; 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; }?>

The program running result is:

Array(    [0] => (5-1/5)*5    [1] => 5*(5-1/5))