COMPLEJIDAD POSTORDEN

                                                                              //O(1)
    private void  postOrden(NodoBin<T> r, ListaCD<T> l){                        //T=1+MAX(2+2+2) = 7
        if(r!=null){                                                            //1+MAX
            postOrden(r.getIzq(), l);                                        //2
            postOrden(r.getDer(), l);                                        //2
            l.insertarAlFinal(r.getInfo());                                //2
        }
    }
T=1+MAX(2+2+2) = 7

T=7

O(1)