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php实现单链表的方法:首先写出链表节点的类;然后在链表中还定义两个方法,分别是插入和删除;接着获取链表长度并添加节点数据;最后获取节点名字并进行删除或更新操作即可。
本文操作环境:Windows7系统、PHP7.1、Dell G3电脑。
用PHP实现的单链表
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。
首先,我们写出链表节点的类。单链表中的每一个节点,都保存其数据域和后驱指针
//链表节点 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; } }
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。
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//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>"; } } //判断连表是否为空 public function isEmpty(){ return $this->header == null; } //清空链表 public function clear(){ $this->header = 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 = $current->next; } } //获取节点名字 public function getLinkNameById($id) { $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; } return $current->name; } //更新节点名称 public function updateLink($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; } 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 ( 5 ); $lists->getLinkList (); echo "<br>-----------更新节点名称--------------<br>"; $lists->updateLink ( 3, "222222" ); $lists->getLinkList (); echo "<br>-----------获取节点名称--------------<br>"; echo $lists->getLinkNameById ( 5 ); echo "<br>-----------获取链表长度--------------<br>"; echo $lists->getLinkLength ();
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