Quick Sort

 1 <?php 2 function sortQuick($a){ # a is an array of numbers 3  4     # length of a 5     $m = count($a); 6      7     if($m < 2){ 8         return $a; 9     }10     11     $pivot = $a[0];12     13     // declare two partitions14     $left = $right = array();15     16     for($i = 1; $i < $m; $i++){17         if($a[$i] < $pivot){18             $left[] = $a[$i];19         }20         else{21             $right[] = $a[$i];22         }23     }24     25     // use recursion to now sort the left and right lists26     return array_merge(sortQuick($left), array($pivot), sortQuick($right));27 }28 29 $arr = range(5, 0);30 echo implode(', ', sortQuick($arr));31 32 // 0, 1, 2, 3, 4, 533 ?>