(define prize-values
  '(10 10 10 10 10 10 10 10 10
    9 9 9
    8 8
    7 7 7 7
    6 6 6
    5 5 5 5
    4 4 4
    3 3 3
    2 2 2 2
    1 1))

(define count-combos
  (lambda (prizes amount)
    (cond ((= amount 0) 1)
          ((< amount 0) 0)
          ((null? prizes) 0)
          (else
           (+ (count-combos prizes (- amount (car prizes)))
              (count-combos (cdr prizes) amount))))))

(define count-combos-saving
  (lambda (prizes amount)
    (cond ((= amount 0) 1)
          ((< amount 0) 0)
          ((null? prizes) 1)
          (else
           (+ (count-combos-saving prizes (- amount (car prizes)))
              (count-combos-saving (cdr prizes) amount))))))