203. Remove Linked List Elements java solutions

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.

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/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode removeElements(ListNode head, int val) {
        if(head == null) return head;
        ListNode ans = new ListNode(-1);
        ListNode tmp = new ListNode(-1);
        ans.next = tmp;
        ListNode cur = head;
        while(cur != null){
            if(cur.val != val) {
                tmp.next = cur;
                tmp = tmp.next;
            }
            cur = cur.next;
        }
        tmp.next = null;
        return ans.next.next;
    }
}