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;;;; License: CC0-1.0
(define-module (net ricketyspace sicp two nineteen)
#:export (us-coins uk-coins cc))
(define us-coins (list 50 25 10 5 1))
(define uk-coins (list 100 50 20 10 5 2 1 0.5))
(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 (no-more? coin-values)
(null? coin-values))
(define (except-first-denomination coin-values)
(cdr coin-values))
(define (first-denomination coin-values)
(car coin-values))
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