PHP双向链表定义与用法示例php技巧

本文实例讲述了PHP双向链表定义与用法。分享给大家供大家参考，具体如下：

由于需要对一组数据多次进行移动操作，所以写个双向链表。但对php实在不熟悉，虽然测试各个方法没啥问题，就是不知道php语言深层的这些指针和unset有什么注意的地方，贴出来让大家教育吧。效率没测试....求谅解～

 ?php * **双向链表 * @author zhiyuan12@ * 链表元素结点类html' target='_blank'>class Node_Element { public $pre = NULL; // 前驱 public $next = NULL; // 后继 public $key = NULL; // 元素键值 public $data = NULL; // 结点值 function __Construct($key, $data) { $this- key = $key; $this- data = $data; * 双向链表类class DoubleLinkedList { private $head; // 头指针 private $tail; // 尾指针 private $current; // 当前指针 private $len; // 链表长度 function __Construct() { $this- head = self::_getNode ( null, null ); $this- curelement = $this- head; $this- tail = $this- head; $len = 0; * @ desc: 读取链表全部结点 public function readAll() { $tmp = $this- head; while ( $tmp- next !== null ) { $tmp = $tmp- next; var_dump ( $tmp- key, $tmp- data ); public function move($pos1, $pos2) { $pos1Node = $this- findPosition ( $pos1 ); $pos2Node = $this- findPosition ( $pos2 ); if ($pos1Node !== null $pos2Node !== null) { $tmpKey = $pos1Node-  $tmpData = $pos1Node- data; $pos1Node- key = $pos2Node-  $pos1Node- data = $pos2Node- data; $pos2Node- key = $tmpKey; $pos2Node- data = $tmpData; return true; return false; * @ desc: 在指定关键词删除结点 * @param : $key * 指定位置的链表元素key public function delete($key) { $pos = $this- find ( $key ); if ($pos !== null) { $tmp = $pos; $last = null; $first = true; while ( $tmp- next !== null $tmp- next- key === $key ) { $tmp = $tmp- next; if (! $first) { $this- delNode ( $last ); } else { $first = false; $last = $tmp; if ($tmp- next !== null) { $pos- pre- next = $tmp- next; $tmp- next- pre = $pos-  } else { $pos- pre- next = null; $this- delNode ( $pos ); $this- delNode ( $tmp ); * @ desc: 在指定位置删除结点 * @param : $key * 指定位置的链表元素key public function deletePosition($pos) { $tmp = $this- findPosition ( $pos ); if ($tmp === null) { return true; if ($tmp === $this- getTail ()) { $tmp- pre- next = null; $this- delNode ( $tmp ); return true; $tmp- pre- next = $tmp- next; $tmp- next- pre = $tmp-  $this- delNode ( $tmp ); * @ desc: 在指定键值之前插入结点 * @param : $key * //指定位置的链表元素key * @param : $data * //要插入的链表元素数据 * @param : $flag * //是否顺序查找位置进行插入 public function insert($key, $data, $flag = true) { $newNode = self::_getNode ( $key, $data ); $tmp = $this- find ( $key, $flag ); if ($tmp !== null) { $newNode- pre = $tmp-  $newNode- next = $tmp; $tmp- pre = $newNode; $newNode- pre- next = $newNode; } else { $newNode- pre = $this- tail; $this- tail- next = $newNode; $this- tail = $newNode; $this- len ++; * @ desc: 在指定位置之前插入结点 * @param : $pos * 指定插入链表的位置 * @param : $key * 指定位置的链表元素key * @param : $data * 要插入的链表元素数据 public function insertPosition($pos, $key, $data) { $newNode = self::_getNode ( $key, $data ); $tmp = $this- findPosition ( $pos ); if ($tmp !== null) { $newNode- pre = $tmp-  $newNode- next = $tmp; $tmp- pre = $newNode; $newNode- pre- next = $newNode; } else { $newNode- pre = $this- tail; $this- tail- next = $newNode; $this- tail = $newNode; $this- len ++; return true; * @ desc: 根据key值查询指定位置数据 * @param : $key * //指定位置的链表元素key * @param : $flag * //是否顺序查找 public function find($key, $flag = true) { if ($flag) { $tmp = $this- head; while ( $tmp- next !== null ) { $tmp = $tmp- next; if ($tmp- key === $key) { return $tmp; } else { $tmp = $this- getTail (); while ( $tmp- pre !== null ) { if ($tmp- key === $key) { return $tmp; $tmp = $tmp-  return null; * @ desc: 根据位置查询指定位置数据 * @param : $pos * //指定位置的链表元素key public function findPosition($pos) { if ($pos = 0 || $pos $this- len) return null; if ($pos ($this- len / 2 + 1)) { $tmp = $this- head; $count = 0; while ( $tmp- next !== null ) { $tmp = $tmp- next; $count ++; if ($count === $pos) { return $tmp; } else { $tmp = $this- tail; $pos = $this- len - $pos + 1; $count = 1; while ( $tmp- pre !== null ) { if ($count === $pos) { return $tmp; $tmp = $tmp-  $count ++; return null; * @ desc: 返回链表头节点 public function getHead() { return $this- head- next; * @ desc: 返回链表尾节点 public function getTail() { return $this- tail; * @ desc: 查询链表节点个数 public function getLength() { return $this-  private static function _getNode($key, $data) { $newNode = new Node_Element ( $key, $data ); if ($newNode === null) { echo new node fail!  return $newNode; private function delNode($node) { unset ( $node ); $this- len --;$myList = new DoubleLinkedList ();$myList- insert ( 1, test1 );$myList- insert ( 2, test2 );$myList- insert ( 2b , test2-b );$myList- insert ( 2, test2-c );$myList- insert ( 3, test3 );$myList- insertPosition ( 5, t , testt );$myList- readAll ();echo +++ $myList- deletePosition(0);$myList- readAll ();echo ... . $myList- getLength ();var_dump ( $myList- findPosition ( 3 )- data );? 

运行结果：

int(1)string(5) test1 int(2)string(7) test2-c int(2)string(5) test2 string(2) 2b string(7) test2-b string(1) t string(5) testt int(3)string(5) test3 +++int(1)string(5) test1 int(2)string(7) test2-c int(2)string(5) test2 string(2) 2b string(7) test2-b string(1) t string(5) testt int(3)string(5) test3 ...6string(5) test2 

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以上就是PHP双向链表定义与用法示例php技巧的详细内容，PHP教程

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