public void split(ref Treap <T> left, ref Treap <T> right, T key)
{
Treap <T> res = new Treap <T>();
copy(root, ref res.root);
split(ref res.root, ref left.root, ref right.root, new node <T>(key));
}
public void join(Treap <T> t)
{
join(t.getroot());
}
public void split(ref Treap <T> left, ref Treap <T> right, T key)
{
split(root, left.getroot(), right.getroot(), new node <T> (key));
}