本文实例讲述了PHP实现单链表翻转操作。分享给大家供大家参考,具体如下:
当一个序列中只含有指向它的后继结点的链接时,就称该链表为单链表。
这里给出了一个单链表的定义及翻转操作方法:
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<?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(); ?> |
运行结果:
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希望本文所述对大家PHP程序设计有所帮助。
原文链接:http://blog.csdn.net/u013474436/article/details/50773736