(define (heapsort lista)
  (define (wstaw xs)
    (if (= (length xs) 0)
        leaf
        (heap-insert (make-elem (car xs) (car xs)) (wstaw (cdr xs)))))
  (define (wynik h)
    (if (heap-empty? h)
        (list)
        (append (list (elem-val (heap-min h))) (wynik (heap-pop h)))))
  (wynik (wstaw lista))

  )

(define x (list 2 3 1))
(define y (list))
(define z (list 2 2 2 3 1 0 5 4 7))
(heapsort x)
(heapsort y)
(heapsort z)