php实现单链表与环形链表

 

 

1.php实现单链表

 

<span style="color:#000000">class singleLink
{
    public $id;
    public $name;
    public $next;

    public function __construct($id=null, $name=null)
    {
        $this->id = $id;
        $this->name = $name;
        $this->next = null;
    }

    //输出单链表
    public function showLink($head)
    {
        $current = $head;
        while ($current->next != null) {
            echo $current->next->id."-->".$current->next->name."<br>";
            $current = $current->next;
        }
    }

    //增加节点
    public function addLink($head, $id, $name)
    {
        $link = new singleLink($id, $name);     //实例化新节点
        $current = $head;     //临时指针指向头节点
        while ($current->next != null) {     //找出插入节点处
            if ($current->next->id > $id) {
                break;
            }
            $current = $current->next;
        }
        $link->next = $current->next;   //插入节点
        $current->next = $link;
    }


    //删除节点
    public function delLink($head, $id)
    {
        $current = $head;
        while ($current->next != null) {
            if ($current->next->id == $id) {
                break;
            }
            $current = $current->next;
        }
        $current->next = $current->next->next;
    }

    //修改节点
    public function updateLink($head, $id, $name)
    {
        $current = $head;
        while ($current->next != null) {
            if ($current->next->id == $id) {
                break;
            }
            $current = $current->next;
        }
        $current->next->name = $name;
    }

    //根据id查找name
    public function getName($head, $id)
    {
        $current = $head;
        while ($current->next != null) {
            if ($current->next->id == $id) {
                break;
            }
            $current = $current->next;
        }
        echo $current->next->name."<br>";
    }
}

//初始化单链表
$single = new singleLink();
echo "-----------添加节点1-----------<br>";
$single->addLink($single,1,'路飞');
$single->addLink($single,7,'鸣人');
$single->addLink($single,3,'柯南');
$single->addLink($single,6,'孙悟空');
$single->showLink($single);
echo "-----------查找节点3的名称-----------<br>";
$single->getName($single,3);
echo "-----------修改节点7-----------<br>";
$single->updateLink($single,7,"漩涡鸣人");
$single->showLink($single);
echo "--------------删除节点6---------------<br>";
$single->delLink($single,6);
$single->showLink($single);</span>

 

2.php用环形链表解决约瑟夫问题

 

1、一群人($sum)围在一起坐成环状

2、从某个编号($start)开始报数

3、数到某个数($num)的时候，此人出列，下一个人重新报数

4、一直循环，直到所有人出列，约瑟夫环结束

class circleLink
{
    private $id;
    private $next;
    private $head;

    public function __construct($id=null, $next=null)
    {
        $this->id = $id;
        $this->next = $next;
    }

    public function Joseph($sum, $num, $start)
    {
        $cur = null;
        for ($i = 1; $i < $sum+1; $i++) {
            $newCircle = new circleLink($i);
            if ($i == 1) {
                $this->head = $newCircle;
                $this->head->next = $newCircle;
                $cur = $this->head;
            } else {
                $cur->next = $newCircle;
                $cur->next->next = $this->head;
                $cur = $cur->next;
            }
        }

        $pre = $this->head;
        while ($pre->next != $this->head) {
            $pre = $pre->next;
        }

        if ($start != null) {
            for ($i = 1; $i < $start; $i++) {
                $this->head = $this->head->next;
                $pre = $pre->next;
            }
        }

        while ($pre != $this->head) {
            for ($i = 0; $i < $num-1; $i++) {
                $this->head = $this->head->next;
                $pre = $pre->next;
            }
            echo "出队的数为：".$this->head->id."<br>";
            $pre->next = $this->head->next;
            $this->head = $this->head->next;
        }
        echo "最后留下的数为：".$this->head->id;
    }
}


$circle = new CircleLink();
$circle->Joseph(5,2,1);