PHP实现单链表翻转操作示例

<?php/** * @file reverseLink.php * @author showersun * @date 2016/03/01 10:33:25 **/class Node{  private $value;  private $next;  public function __construct($value=null){    $this->value = $value;  }  public function getValue(){    return $this->value;  }  public function setValue($value){    $this->value = $value;  }  public function getNext(){    return $this->next;  }  public function setNext($next){    $this->next = $next;  }}//遍历，将当前节点的下一个节点缓存后更改当前节点指针 function reverse($head){  if($head == null){    return $head;  }  $pre = $head;//注意：对象的赋值  $cur = $head->getNext();  $next = null;  while($cur != null){    $next = $cur->getNext();    $cur->setNext($pre);    $pre = $cur;    $cur = $next;  }  //将原链表的头节点的下一个节点置为null，再将反转后的头节点赋给head   $head->setNext(null);  $head = $pre;  return $head;}//递归，在反转当前节点之前先反转后续节点 function reverse2($head){  if (null == $head || null == $head->getNext()) {    return $head;  }  $reversedHead = reverse2($head->getNext());  $head->getNext()->setNext($head);  $head->setNext(null);  return $reversedHead;}function test(){  $head = new Node(0);  $tmp = null;  $cur = null;  // 构造一个长度为10的链表，保存头节点对象head    for($i=1;$i<10;$i++){    $tmp = new Node($i);    if($i == 1){      $head->setNext($tmp);    }else{      $cur->setNext($tmp);    }    $cur = $tmp;  }  //print_r($head);exit;  $tmpHead = $head;  while($tmpHead != null){    echo $tmpHead->getValue().' ';    $tmpHead = $tmpHead->getNext();  }  echo "/n";  //$head = reverse($head);  $head = reverse2($head);  while($head != null){    echo $head->getValue().' ';    $head = $head->getNext();  }}test();?>

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