203. Remove Linked List Elements

    public static ListNode removeElements(ListNode head, int val) {        if(head == null) {            return null;        }        ListNode pre = null, cur = head;        while(cur != null) {            if(cur.val == val) {                if(pre == null) {                    head = cur.next;                    cur = cur.next;                }else {                    cur = cur.next;                    pre.next = cur;                }            }else {                pre =cur;                cur = cur.next;            }        }        return head;     }