public ArrayList<TreeLinkNode> getChildren(ArrayList<TreeLinkNode> root) {
		ArrayList<TreeLinkNode> result = new ArrayList<TreeLinkNode>();
		for (TreeLinkNode t : root) {
			if (t.left != null)
				result.add(t.left);
			if (t.right != null)
				result.add(t.right);
		}
		return result;
	}