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用PHP实现的单链表
发布时间：2017-12-13 14:15:30编辑：PHPChina-春阳查看次数：1194
单链表顾名思义就是一个链式数据结构，它有一个表头，并且除了最后一个节点外，所有节点都有其后继节点。如下图。
链表中还有两个特别重要的方法，插入和删除。插入需要找到插入的位置，把前一个元素的next指针指向被插入的节点，并将被插入节点的next指针指向后一个节点，如下图左侧所示。而删除则是把前一个节点的next指针指向后一个节点，并返回被删除元素的数据内容，如下图右侧所示。
<?php
class node {
public $id; //节点id
public $name; //节点名称
public $next; //下一节点
public function __construct($id, $name) {
$this->id = $id;
$this->name = $name;
$this->next = null;
}
}
//单链表
class singelLinkList {
private $header; //链表头节点
//构造方法
public function __construct($id = null, $name = null) {
$this->header = new node ( $id, $name, null );
}
//获取链表
public function getLinkList() {
$current = $this->header;
if ($current->next == null) {
echo ("链表为空!");
return;
}
while ( $current->next != null ) {
echo 'id:' . $current->next->id . ' name:' . $current->next->name . "<br>";
if ($current->next->next == null) {
break;
}
$current = $current->next;
}
}
//获取链表长度
public function getLinkLength() {
$i = 0;
$current = $this->header;
while ( $current->next != null ) {
$i ++;
$current = $current->next;
}
return $i;
}
//添加节点数据
public function addLink($node) {
$current = $this->header;
while ( $current->next != null ) {
if ($current->next->id > $node->id) {
break;
}
$current = $current->next;
}
$node->next = $current->next;
$current->next = $node;
}
//删除链表节点
public function delLink($id) {
$current = $this->header;
$flag = false;
while ( $current->next != null ) {
if ($current->next->id == $id) {
$flag = true;
break;
}
$current = $current->next;
}
if ($flag) {
$current->next = $current->next->next;
} else {
echo "未找到id=" . $id . "的节点！<br>";
}
}
//更新节点名称
public function updateLink($id, $name) {
$current = $this->header;
if ($current->next == null) {
echo "链表为空!";
return;
}
while ( $current->next != null ) {
if ($current->id == $id) {
break;
}
$current = $current->next;
}
if ($current->next == null) {
echo "未找到id=" . $id . "的节点！<br>";
return;
}
return $current->name = $name;
}
}
$lists = new singelLinkList ();
$lists->addLink ( new node ( 5, 'eeeeee' ) );
$lists->addLink ( new node ( 1, 'aaaaaa' ) );
$lists->addLink ( new node ( 6, 'ffffff' ) );
$lists->addLink ( new node ( 4, 'dddddd' ) );
$lists->addLink ( new node ( 3, 'cccccc' ) );
$lists->addLink ( new node ( 2, 'bbbbbb' ) );
$lists->getLinkList ();
echo "<br>-----------删除节点--------------<br>";
$lists->delLink ( 6 );
$lists->getLinkList ();
echo "<br>-----------更新节点名称--------------<br>";
$lists->updateLink ( 3, "222222" );
$lists->getLinkList ();
echo "<br>-----------获取链表长度--------------<br>";
echo $lists->getLinkLength ();
关键字词：PHP,单链表,数据结构,算法
