code: private Node<T> rotateRight(Node<T> h) {
  		// assert (h != null) && isRed(h.left);
  		Node<T> x = h.left;
  		h.left = x.right;
  		x.right = h;
  		x.red = x.right.red;
  		x.right.red = true;
  		x.n = h.n;
  		h.n = (h.left == null ? 0 : h.left.n) + (h.right == null ? 0 : h.right.n) + 1;
  		return x;
      }
docs: make a left-leaning link lean to the right