PHP小教程之實現(xiàn)雙向鏈表

更新時間：2014年06月12日 09:06:29 投稿：hebedich

雙向鏈表也叫雙鏈表，是鏈表的一種，它的每個數(shù)據(jù)結點中都有兩個指針，分別指向直接后繼和直接前驅。所以，從雙向鏈表中的任意一個結點開始，都可以很方便地訪問它的前驅結點和后繼結點。一般我們都構造雙向循環(huán)鏈表。

看了很久數(shù)據(jù)結構但是沒有怎么用過，在網(wǎng)上看到了關于PHP的數(shù)據(jù)結構，學習了一下，與大家一起分享一下。上一次分享了《PHP小教程之實現(xiàn)鏈表》，這次來補充說一下雙向鏈表。

<?php
        class Hero
        {
            public $pre=null;
            public $no;
            public $name;
            public $next=null;
            public function __construct($no='',$name='')
            {
                $this->no=$no;
                $this->name=$name;
            }
            static public function addHero($head,$hero)
            {
                $cur = $head;
                $isExist=false;
                //判斷目前這個鏈表是否為空
                if($cur->next==null)
                {
                    $cur->next=$hero;
                    $hero->pre=$cur;
                }
                else
                {
                    //如果不是空節(jié)點，則安排名來添加
                    //找到添加的位置
                    while($cur->next!=null)
                    {
                        if($cur->next->no > $hero->no)
                        {
                            break;
                        }
                        else if($cur->next->no == $hero->no)
                        {
                            $isExist=true;
                            echo "<br>不能添加相同的編號";
                        }
                        $cur=$cur->next;
                    }
                    if(!$isExist)
                    {
                        if($cur->next!=null)
                        {
                            $hero->next=$cur->next;
                        }
                        $hero->pre=$cur;
                        if($cur->next!=null)
                        {
                            $hero->next->pre=$hero;
                        }
                        $cur->next=$hero;                    
                    }
                }
            }
            //遍歷
            static public function showHero($head)
            {
                $cur=$head;
                while($cur->next!=null)
                {
                    echo "<br>編號：".$cur->next->no."名字：".$cur->next->name;
                    $cur=$cur->next;
                }
            }
            static public function delHero($head,$herono)
            {
                $cur=$head;
                $isFind=false;
                while($cur!=null)
                {
                    if($cur->no==$herono)
                    {
                        $isFind=true;
                        break;
                    }
                    //繼續(xù)找
                    $cur=$cur->next;
                }
                if($isFind)
                {
                    if($cur->next!=null)
                    {
                        $cur->next_pre=$cur->pre;
                    }
                    $cur->pre->next=$cur->next;
                }
                else
                {
                    echo "<br>沒有找到目標";
                }                
            }
        }
        $head = new Hero();
        $hero1 = new Hero(1,'1111');
        $hero3 = new Hero(3,'3333');
        $hero2 = new Hero(2,'2222');
        Hero::addHero($head,$hero1);
        Hero::addHero($head,$hero3);
        Hero::addHero($head,$hero2);
        Hero::showHero($head);
        Hero::delHero($head,2);
        Hero::showHero($head);
?>