suzanne.soy/racket
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Works on lists of any size now.

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svn: r17004
This commit is contained in:
Eli Barzilay 2009-11-23 18:48:46 +00:00
parent c68eeb97ca
commit d46beb2325
1 changed files with 14 additions and 10 deletions
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24
collects/scheme/private/sort.ss
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@ -59,17 +59,21 @@ doing these checks.
(define (copying-mergesort Alo Ahi Blo Bhi)
(unless (= (- Ahi Alo) (- Bhi Blo)) (error "poof!!!"))
(cond [(< Alo (sub1 Ahi))
(let ([Amid (/ (+ Alo Ahi) 2)] [Bmid (/ (+ Blo Bhi) 2)])
(copying-mergesort Amid Ahi Bmid Bhi)
(copying-mergesort Alo Amid Amid Ahi)
(merge #t Amid Ahi Bmid Bhi Blo Bhi))]
(let ([Amid1 (floor (/ (+ Alo Ahi) 2))]
[Amid2 (ceiling (/ (+ Alo Ahi) 2))]
[Bmid1 (floor (/ (+ Blo Bhi) 2))]
[Bmid2 (ceiling (/ (+ Blo Bhi) 2))])
(copying-mergesort Amid1 Ahi Bmid1 Bhi)
(copying-mergesort Alo Amid1 Amid2 Ahi)
(merge #t Amid2 Ahi Bmid1 Bhi Blo Bhi))]
[(= Alo (sub1 Ahi))
(set! Blo (ref Alo))]))
(let ([Alo 0] [Amid n/2] [Ahi n] [B1lo n] [B1hi (+ n n/2)])
(copying-mergesort Amid Ahi B1lo B1hi)
(copying-mergesort Alo Amid Amid Ahi)
(merge #f B1lo B1hi Amid Ahi Alo Ahi))))
(let ([Alo 0] [Amid1 (- n n/2)] [Amid2 n/2] [Ahi n]
[B1lo n] [B1hi (+ n n/2)])
(copying-mergesort Amid1 Ahi B1lo B1hi)
(copying-mergesort Alo Amid1 Amid2 Ahi)
(merge #f B1lo B1hi Amid2 Ahi Alo Ahi))))
(define sort-internals (make-hasheq))
(define _
@ -107,7 +111,7 @@ doing these checks.
[cache-keys?
;; decorate while converting to a vector, and undecorate when going
;; back, always do this for consistency
(let ([vec (make-vector (+ n (/ n 2)))])
(let ([vec (make-vector (+ n (ceiling (/ n 2))))])
;; list -> decorated-vector
(let loop ([i 0] [lst lst])
(when (pair? lst)
@ -154,7 +158,7 @@ doing these checks.
(if (<? c a) (list b c a) (list b a c)))
;; a<=b, so c<b (b<=c is impossible due to above test)
(if (<? c a) (list c a b) (list a c b))))))]
[else (let ([vec (make-vector (+ n (/ n 2)))])
[else (let ([vec (make-vector (+ n (ceiling (/ n 2))))])
;; list -> vector
(let loop ([i 0] [lst lst])
(when (pair? lst)