<?php

/**

* Definition for a singly-linked list.

* class ListNode {

* public $val = 0;

* public $next = null;

* function __construct($val = 0, $next = null) {

* $this->val = $val;

* $this->next = $next;

* }

* }

*/

class ListNode {

public $val = 0;

public $next = null;

function __construct($val = 0, $next = null) {

$this->val = $val;

$this->next = $next;

}

}

/**

* 给你一个链表的头节点 head 和一个整数 val ，请你删除链表中所有满足 Node.val == val 的节点，并返回 新的头节点 。

* @param ListNode $head

* @param Integer $val

* @return ListNode

*/

function removeElements($head, $val) {

$virtual_head = new ListNode(null);

$virtual_head->next = $head;

//设置前节点

$pre = $virtual_head;

//当前节点

$cur = $virtual_head->next;

while ($cur != null){

if($cur->val == $val){

//不再指向该节点

$pre->next = $cur->next;

}else{

$pre = $cur;

}

$cur = $cur->next;

}

return $virtual_head->next;

}