;; CHF - swiss franc -using block approach

;; cc amount 7 - number of coin types
(define (count-change amount)
  (define (cc amount kinds-of-coins)
    (cond ((= amount 0) 1)
          ((or (< amount 0) (= kinds-of-coins 0)) 0)
          (else (+ (cc amount
                       (- kinds-of-coins 1))
                   (cc (- amount
                          (first-denomination kinds-of-coins))
                       kinds-of-coins)))))
  (define (first-denomination kinds-of-coins)
    (cond ((= kinds-of-coins 1) 5)
          ((= kinds-of-coins 2) 10)
          ((= kinds-of-coins 3) 20)
          ((= kinds-of-coins 4) 50)
          ((= kinds-of-coins 5) 100)
          ((= kinds-of-coins 6) 200)
          ((= kinds-of-coins 7) 500)))
  (cc amount 7))

;; lets try it out
(count-change 300)
;; expected 1022

(count-change 301)
;; expected 0 because no pennies



;; alternative coin order - shouldn't make a difference - lets be sure
(define (count-change-2 amount)
  (define (cc amount kinds-of-coins)
    (cond ((= amount 0) 1)
          ((or (< amount 0) (= kinds-of-coins 0)) 0)
          (else (+ (cc amount
                       (- kinds-of-coins 1))
                   (cc (- amount
                          (first-denomination kinds-of-coins))
                       kinds-of-coins)))))
  (define (first-denomination kinds-of-coins)
    (cond ((= kinds-of-coins 1) 500)
          ((= kinds-of-coins 2) 5)
          ((= kinds-of-coins 3) 50)
          ((= kinds-of-coins 4) 100)
          ((= kinds-of-coins 5) 20)
          ((= kinds-of-coins 6) 200)
          ((= kinds-of-coins 7) 10)))
  (cc amount 7))

;; lets try it out
(count-change-2 300)
;; expected 1022

(count-change-2 301)
;; expected 0 because no pennies