Created
February 20, 2011 04:32
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All sorts of sorting algorithms written in Scheme (Gauche)
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(use srfi-27) | |
(use srfi-42) | |
(define-macro (swap! a b) | |
(let1 t (gensym) | |
`(let1 ,t ,a | |
(set! ,a ,b) | |
(set! ,b ,t)))) | |
(define (bubble-sort v) | |
(let ((v (vector-copy v)) | |
(continue #t)) | |
(while continue | |
(set! continue #f) | |
(do-ec (: i (- (vector-length v) 1)) | |
(when (> (vector-ref v i) (vector-ref v (+ i 1))) | |
(swap! (vector-ref v i) (vector-ref v (+ i 1))) | |
(set! continue #t)))) | |
v)) | |
(define (insertion-sort v) | |
(let1 v (vector-copy v) | |
(do-ec (: i 1 (vector-length v)) | |
(let1 e (vector-ref v i) | |
(let l ((j (- i 1))) | |
(if (and (>= j 0) (> (vector-ref v j) e)) | |
(begin | |
(vector-set! v (+ j 1) (vector-ref v j)) | |
(l (- j 1))) | |
(vector-set! v (+ j 1) e))))) | |
v)) | |
(define (selection-sort v) | |
(let ((v (vector-copy v)) | |
(n (vector-length v))) | |
(do-ec (: i (- n 1)) | |
(let l ((j (+ i 1)) (m i)) | |
(if (< j n) | |
(l (+ j 1) | |
(if (< (vector-ref v j) (vector-ref v m)) | |
j m)) | |
(swap! (vector-ref v i) (vector-ref v m))))) | |
v)) | |
(define (merge-sort v) | |
(define (rec ls) | |
(if (<= (length ls) 1) | |
ls | |
(receive (a b) (split-at ls (div (length ls) 2)) | |
(let l ((result '()) (a (rec a)) (b (rec b))) | |
(cond ((and (null? a) (null? b)) | |
(reverse result)) | |
((null? a) | |
(l (cons (car b) result) '() (cdr b))) | |
((null? b) | |
(l (cons (car a) result) (cdr a) '())) | |
((< (car a) (car b)) | |
(l (cons (car a) result) (cdr a) b)) | |
(else (l (cons (car b) result) a (cdr b)))))))) | |
((.$ list->vector rec vector->list) v)) | |
(define (quick-sort v) | |
(let1 v (vector-copy v) | |
(define (partition a b) | |
(let* ((pi (div (+ a b) 2)) | |
(pv (vector-ref v pi)) | |
(j a)) | |
(swap! (vector-ref v pi) (vector-ref v b)) | |
(let l ((i a)) | |
(when (< i b) | |
(when (< (vector-ref v i) pv) | |
(swap! (vector-ref v i) (vector-ref v j)) | |
(inc! j)) | |
(l (+ i 1)))) | |
(swap! (vector-ref v j) (vector-ref v b)) | |
j)) | |
(let rec ((a 0) (b (- (vector-length v) 1))) | |
(when (< a b) | |
(let1 p (partition a b) | |
(rec a (- p 1)) | |
(rec (+ p 1) b)))) | |
v)) | |
; usage: % gosh sort.scm <number of elements (n)> | |
(define (main args) | |
(random-source-randomize! default-random-source) | |
(let* ((n (string->number (cadr args))) | |
(v (vector-ec (: i n) (random-integer n)))) | |
(print v) | |
(print (sort v)) | |
(print (bubble-sort v)) | |
(print (insertion-sort v)) | |
(print (selection-sort v)) | |
(print (merge-sort v)) | |
(print (quick-sort v))) | |
0) |
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