PHP实现链表的定义与反转功能示例

<?php
class node
{
  private $data;//节点数据
  private $next;//下一节点
 
  public function setdata($value){
    $this->data=$value;
  }
 
  public function setnext($value){
     $this->next=$value;
  }  
 
  public function getdata(){
    return $this->data;
  }
 
  public function getnext(){
    return $this->next;
  }
 
  public function __construct($data,$next){
    $this->setdata($data);
    $this->setnext($next);
  }
}
class linklist
{
  private $header;//头节点
  private $size;//长度
  public function getsize()
 {
    $i=0;
    $node=$this->header;
    while($node->getnext()!=null)
    {  
  $i++;
      $node=$node->getnext();
    }
    return $i;
  }
 
  public function setheader($value){
    $this->header=$value;
  }
 
  public function getheader(){
    return $this->header;
  }
 
  public function __construct(){
    header("content-type:text/html; charset=utf-8");
    $this->setheader(new node(null,null));
  }
  /**
  *@author mzxy
  *@param $data--要添加节点的数据
  * 
  */
  public function add($data)
  {
    $node=$this->header;
    while($node->getnext()!=null)
    {
      $node=$node->getnext();
    }
    $node->setnext(new node($data,null));
  }
   /**
  *@author mzxy
  *@param $data--要移除节点的数据
  * 
  */
  public function removeat($data)
  {
    $node=$this->header;
    while($node->getdata()!=$data)
    {
      $node=$node->getnext();
    }
    $node->setnext($node->getnext());
    $node->setdata($node->getnext()->getdata());
  }
   /**
  *@author mzxy
  *@param 遍历
  * 
  */
  public function get()
  {
    $node=$this->header;
    if($node->getnext()==null){
      print("数据集为空!");
      return;
    }
    while($node->getnext()!=null)
    {
      print('['.$node->getnext()->getdata().'] -> ');
      if($node->getnext()->getnext()==null){break;}
      $node=$node->getnext();
    }
  }
   /**
  *@author mzxy
  *@param $data--要访问的节点的数据
  * @param 此方法只是演示不具有实际意义
  * 
  */
  public function getat($data)
  {
    $node=$this->header->getnext();
  if($node->getnext()==null){
      print("数据集为空!");
      return;
    }
    while($node->getdata()!=$data)
    {
      if($node->getnext()==null){break;}
      $node=$node->getnext();
    }
    return $node->getdata();    
  }
   /**
  *@author mzxy
  *@param $value--需要更新的节点的原数据 --$initial---更新后的数据
  * 
  */
  public function update($initial,$value)
  {
     $node=$this->header->getnext();
 if($node->getnext()==null){
     print("数据集为空!");
      return;
    }
    while($node->getdata()!=$data)
    {
      if($node->getnext()==null){break;}
      $node=$node->getnext();
    }
 $node->setdata($initial);   
  }
}
$lists = new linklist();
$lists -> add(1);
$lists -> add(2);
$lists -> get();
echo '<pre>';
print_r($lists);
echo '</pre>';
?>

function reverselist($phead)
{
  // write code here
  if($phead == null || $phead->next == null){
    return $phead;
  }
  $p = $phead;
  $q = $phead->next;
  $phead->next = null;//$phead 变为尾指针
  while($q){
    $r = $q->next;
    $q->next = $p;
    $p = $q;
    $q = $r;
  }
  return $p;
}

function reverselist($phead)
{
  // write code here
  if($phead == null || $phead->next == null){
    return $phead;
  }
  $res = reverselist($phead->next);
  $phead->next->next = $phead;
  $phead->next = null;
  return $res;
}