Exercise 2.19.rkt

#lang sicp

(define us-coins (list 50 25 10 5 1))
(define uk-coins (list 100 50 20 10 5 2 1 0.5))
(define euro-coins (list 200 100 50 20 10 5 2 1))

(define (cc amount coin-values)
  (cond ((= amount 0) 1)
        ((or (< amount 0) (no-more? coin-values)) 0)
        (else
         (+ (cc amount
                (except-first-denomination coin-values))
            (cc (- amount (first-denomination coin-values))
                coin-values)))))

(define (first-denomination l) (car l))
(define (except-first-denomination l) (cdr l))
(define (no-more? l) (null? l))

(cc 100 euro-coins)
(cc 100 (reverse euro-coins))