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authorrsiddharth <s@ricketyspace.net>2016-11-12 02:52:06 +0000
committerrsiddharth <s@ricketyspace.net>2016-11-12 02:52:06 +0000
commit5bf0b73c2aff8613c3db3188356d4735ca6506a3 (patch)
tree312152a0ed927c71e87abf52a97e69842db9039c /one
parent4cb8f74731ee1277404085746d8e1da7cd549476 (diff)
add one/fourteen.scm
Diffstat (limited to 'one')
-rw-r--r--one/fourteen.scm29
1 files changed, 29 insertions, 0 deletions
diff --git a/one/fourteen.scm b/one/fourteen.scm
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+;;;; Under Creative Commons Attribution-ShareAlike 4.0
+;;;; International. See
+;;;; <https://creativecommons.org/licenses/by-sa/4.0/>.
+
+;;; source from section 1.2.2
+
+(define-module (one fourteen)
+ #:export (count-change
+ cc
+ first-denomination))
+
+(define (count-change amount)
+ (cc amount 5))
+
+(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) 1)
+ ((= kinds-of-coins 2) 5)
+ ((= kinds-of-coins 3) 10)
+ ((= kinds-of-coins 4) 25)
+ ((= kinds-of-coins 5) 50)))