PHP一個簡單的快速排序

通過不斷的定位基準數的位置來實現快速排序

<?php
/**


Created by PhpStorm.
User: saint
Date: 15/8/5
Time: 上午11:49
*/
class Demo
{
 public $a = array(3, 6, 9, 2, 4, 7, 1, 5, 8, 0);
public function qsort($left, $right)
 {

 if($left > $right) {
     return;
 }

 $i = $left;
 $j = $right;
 $standard = $this->a[$left];

 while($i != $j) {

     // 從右向左查找比基準數小的單元
     while(($standard <= $this->a[$j]) && ($j > $i)) {
         $j--;
     }

     // 從左到右查找比基準數大的
     while(($standard >= $this->a[$i]) && ($j > $i)) {
         $i++;
     }

     $tmp = $this->a[$i];
     $this->a[$i] = $this->a[$j];
     $this->a[$j] = $tmp;
 }

 // 確定基準數的位置
 $this->a[$left] = $this->a[$i];
 $this->a[$i] = $standard;

 $this->qsort($left, $i - 1);
 $this->qsort($i + 1, $right);

}
// 執行函數
 public function main()
 {

 $left = 0;
 $right = count($this->a) - 1;
 $this->qsort($left, $right);
 print_r($this->a);

}
}


$demo = new Demo();
$demo->main();</pre> 

 來自：http://my.oschina.net/liuke1556/blog/488215