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authorrsiddharth <s@ricketyspace.net>2016-11-26 02:00:46 +0000
committerrsiddharth <s@ricketyspace.net>2016-11-26 02:00:46 +0000
commit05406f3d496743112af75ced3fa2e566121f844b (patch)
tree49e08f1a938c5caf76068c1c23ab240f9fa5e7ae /one
parent5bf0b73c2aff8613c3db3188356d4735ca6506a3 (diff)
update one/fourteen.scm
Diffstat (limited to 'one')
-rw-r--r--one/fourteen.scm54
1 files changed, 34 insertions, 20 deletions
diff --git a/one/fourteen.scm b/one/fourteen.scm
index 47156c7..4186238 100644
--- a/one/fourteen.scm
+++ b/one/fourteen.scm
@@ -2,28 +2,42 @@
;;;; International. See
;;;; <https://creativecommons.org/licenses/by-sa/4.0/>.
-;;; source from section 1.2.2
+;;; adapted from section 1.2.2
+;;; intolerable scheme drivel; ignore it.
(define-module (one fourteen)
- #:export (count-change
- cc
- first-denomination))
+ #:export (get-cc
+ cc-range
+ cc-diff-list))
-(define (count-change amount)
- (cc amount 5))
+(define (get-cc)
+ (let ((no-of-steps 0))
+ (define (cc amount kinds-of-coins)
+ (set! no-of-steps (1+ no-of-steps))
+ (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)))
+ (lambda (amount)
+ (cc amount 5)
+ no-of-steps)))
-(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 (cc-range amount limit incr)
+ (cond ((> amount limit) '())
+ ((<= amount limit)
+ (cons ((get-cc) amount)
+ (cc-range (+ amount incr) limit incr)))))
-(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)))
+(define (cc-diff-list l)
+ (cond ((= (length l) 1) '())
+ ((> (length l) 1) (cons (+ (* -1 (car l)) (cadr l))
+ (cc-diff-list (cdr l))))))