Remove Linked List Elements Leetcode JAVA

Remove all elements from a linked list of integers that have value val.

Example

Given: 1 –> 2 –> 6 –> 3 –> 4 –> 5 –> 6, val = 6

Return: 1 –> 2 –> 3 –> 4 –> 5

Credits:

Special thanks to @mithmatt for adding this problem and creating all test cases.

public class Solution {
public ListNode removeElements(ListNode head, int val) {
ListNode preHead=new ListNode(-1);
preHead.next=head;
ListNode pre=preHead;
ListNode cur=head;
while(cur!=null){
if(cur.val==val){
pre.next=cur.next;
}else {
pre=pre.next;
}
if(pre==null)
break;
cur=pre.next;
}
return preHead.next;
}
}