public ListNode(int val = 0, ListNode next = null)
{
this.val = val;
this.next = next;
}
internal void ShiftFirst()
{
firstPointer = firstPointer.next;
}
internal void Shift()
{
firstPointer = firstPointer.next;
secondPointer = secondPointer.next;
}
public ListNodeAddr(ListNode current)
{
headPointer = new ListNode(0, current);
firstPointer = headPointer;
secondPointer = headPointer;
}