PHP实现的静态链表

PHP实现的单链表，如下代码：

    //结点类 
    class Node{ 
        private $next = NULL; //下一个结点指针 
        private $data = NULL; //数据 
    
        public function Node($data, $next = NULL){ 
            $this->data = $data; 
            $next && $this->next = $next; 
        } 
        public function getData(){ 
            return $this->data; 
        } 
        public function setData($data){ 
            $this->data = $data; 
        } 
        public function getNext(){ 
            return $this->next; 
        } 
        public function setNext($next){ 
            $this->next = $next; 
        } 
    } 
 
    //单链表类 
    class LinkList{ 
        private $data_list = NULL; //结点集           
 
        public function LinkList($data = false){ 
            $this->data_list = array(); 
            $title = new Node(NULL); 
            $this->data_list[] = $title; 
           
            if($data){ 
                if(is_array($data)){ 
                    $this->addMoreData($data); 
                }else{ 
                    $this->addData($data); 
                } 
            } 
        } 
        //返回第N个结点的值 
        public function getNodeByNumber($number){ 
            return $this->data_list[$this->findKeyByNumber($number)]->getData(); 
        } 
        //添加一组结点 
        public function addMoreData($datas){ 
            foreach($datas as $value){ 
                $this->addData($value); 
            } 
        } 
        //添加结点统一入口,供外面调用 
        //$number 添加在第几个结点的后面 
        public function addData($data, $number = false){ 
            $node = new Node($data); 
            if($number === FALSE  $number == count($this->data_list)){ 
                $this->insertLastNode($node); 
            }elseif($number > count($this->data_list)){ 
                return false; 
            }else{ 
                $this->insertNode($node, $number); 
            } 
        } 
        //插入一个结点到最后 
        private function insertLastNode($node){ 
                $node->setNext(NULL);              
                $lastKey = $this->findLastNode(); 
                $insert_key = $this->insertNodeIntoArray($node); 
                $this->data_list[$lastKey]->setNext($insert_key); 
        }     
        //插入一个结点 
        private function insertNode($node, $number){ 
            $insert_number = $this->findKeyByNumber($number);     
            $node->setNext($this->data_list[$insert_number]->getNext()); 
            $insert_key = $this->insertNodeIntoArray($node); 
            $this->data_list[$insert_number]->setNext($insert_key); 
        } 
        //查找第N个结点对应的数组key 
        private function findKeyByNumber($number){ 
            $i = $key = 0; 
 
            while($i $number){ 
                $key = $this->data_list[$key]->getNext(); 
                $i ++; 
            } 
          
            return $key; 
        } 
        //将结点加入数组 
        private function insertNodeIntoArray($node){ 
            $this->data_list[] = $node;      
            return $this->getLastKey(); 
        } 
        //删除结点 
        public function deleteNode($number){ 
            if($number == 0  $number > count($this->data_list)){ 
                return false; 
            } 
 
            $pre_key = $this->findKeyByNumber($number - 1); 
            $key = $this->data_list[$pre_key]->getNext(); 
 
          $this->data_list[$pre_key]->setNext($this->data_list[$key]->getNext()); 
            unset($this->data_list[$key]); 
        } 
 
        //查找某结点的前一个结点 
        private function getPreNodeKey($key){ 
            foreach($this->data_list as $k=>$v){ 
                if($v->getNext() == $key){ 
                    return $k;   
                } 
            } 
            return false; 
        } 
 
        //打印链表 
        public function getData_list(){ 
            return $this->data_list; 
        } 
 
        //返回数组的最后一个键 
        private function getLastKey(){ 
            end($this->data_list); 
            return key($this->data_list); 
        } 
 
        //判断某个键值是否存在 
        private function ifExistKey($key){ 
            if(array_key_exists($key, $this->data_list)){ 
                return true; 
            }           
            return false; 
        } 
        //查找尾结点 
        public function findLastNode(){ 
            foreach($this->data_list as $key=>$value){ 
                if($value->getNext() === NULL){ 
                    return $key; 
                } 
            } 
        } 
    } 
?>