PHP算法学习（6） 单向链表 实现栈

svn地址：svn://gitee.com/zxadmin/live_z

这个是模拟栈的先进后出的一个链表操作，自动维护链表，当然你也使用SPL的栈

测试版本php 5.4 ，5.6，7.0,7.2

/*
 * 链表测试到辅助类
 */
 
final class Node {
 
    public $data;
    public $next = null;
 
    public function __construct($data) {
        $this->data = $data;
    }
 
}

<?php
 
/*
 * 单向链表，注意是使用数组模拟单链表到特性，也可以理解为有单向链接到数组
 */
 
final class SinglyLinkedList {
 
    protected $list = null;
 
//    //从链表尾部压入一个节点，节点自动维护，不需要要像main方法那样自己维护
    public function push(Node $head, Node $Node) {
        $current = $head; //让$current指向$head;
        while ($current->next != null) {
            $current = $current->next;
        }
        $current->next = $Node->next;
        $current->next = $Node;
    }
 
    //从链表尾压出一个节点
    public function pop(Node $head) {
        $current = $head; //让$current指向$head;
        while ($current->next != null) {
            //提前查找链表尾部是否为空，为空就是尾部，吧当前节点的next复制问NULL，就是尾部元素干掉
            if ($current->next->next == null) {
                break;
            }
            $current = $current->next;
        }
        $current->next = null;
    }
 
    //非自动维护一个链表，只是单纯点组成一个链表
    public static function main() {
        $header = new Node(null);
 
        $node1 = new Node(['id' => 2, 'name' => '李1']);
        $header->next = $node1;
 
        $node2 = new Node(['id' => 5, 'name' => '李5']);
        $node1->next = $node2;
 
        $node3 = new Node(['id' => 7, 'name' => '李7']);
 
        $node2->next = $node3;
        pp($header);
 
        self::getAllNode($header);
    }
 
    public static function getAllNode($header) {
        $cur = $header;
        while ($cur->next != null) {
            $cur = $cur->next;
            p($cur->data);
        }
    }
 
}

测试

//单链表
$head = new Node([]);
 
$SinglyLinkedList = new SinglyLinkedList();
$node1 = new Node(['id' => 2, 'name' => '李1']);
$SinglyLinkedList->push($head, $node1);
 
//pp($SinglyLinkedList->getList());
$node2 = new Node(['id' => 5, 'name' => '李5']);
$SinglyLinkedList->push($head, $node2);
 
$node3 = new Node(['id' => 7, 'name' => '李7']);
$SinglyLinkedList->push($head, $node3);
 
$SinglyLinkedList->pop($head);
pp($head);