商家自己做的商品信息查询网站,网站开发结论,计算机网络技术毕业设计选题,广药网站建设试卷本文实例讲述了PHP双向链表定义与用法。分享给大家供大家参考#xff0c;具体如下#xff1a;由于需要对一组数据多次进行移动操作#xff0c;所以写个双向链表。但对php实在不熟悉#xff0c;虽然测试各个方法没啥问题#xff0c;就是不知道php语言深层的这些指针和unset…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/*** **双向链表* author zhiyuan12*//*** 链表元素结点类*/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 $pos1Node-key;$tmpData $pos1Node-data;$pos1Node-key $pos2Node-key;$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 $pos-pre;} else {$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 $tmp-pre;$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 $tmp-pre;$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 $tmp-pre;$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-pre;}}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 $tmp-pre;$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 $this-len;}private static function _getNode($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) test1int(2)string(7) test2-cint(2)string(5) test2string(2) 2bstring(7) test2-bstring(1) tstring(5) testtint(3)string(5) test3int(1)string(5) test1int(2)string(7) test2-cint(2)string(5) test2string(2) 2bstring(7) test2-bstring(1) tstring(5) testtint(3)string(5) test3...6string(5) test2希望本文所述对大家PHP程序设计有所帮助。