public void Add(Node child)
{
child.sibling = this.child;
this.child = child;
}
public void Remove(Node previous, Node child)
{
if (previous == this)
{
previous.child = child.sibling;
}
else
{
previous.sibling = child.sibling;
}
}
public static bool IsEmpty(Node node)
{
return node == null;
}