php兑现单链表(静态链表)

<?php    /*     * 单链表的PHP实现     *     * @author zhaojiangwei     * @since 2011/10/20     */    //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;                }            }        }    }?>