203. Remove Linked List Elements

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.

题目含义：删除列表中指定的值

    public ListNode removeElements(ListNode head, int val) {
        if (head == null) return head;
        ListNode pointer = head;
        while (pointer.next != null) {
            if (pointer.next.val == val) pointer.next = pointer.next.next;
            else pointer = pointer.next;
        }
        return head.val == val ? head.next : head;        
    }