95 lines
2.4 KiB
Scheme
95 lines
2.4 KiB
Scheme
|
; The quick-1 benchmark. (Figure 35, page 132.)
|
||
|
|
|
||
|
|
(define (quick-1 v less?)
|
||
|
|
|
||
|
|
(define (helper left right)
|
||
|
|
(if (< left right)
|
||
|
|
(let ((median (partition v left right less?)))
|
||
|
|
(if (< (- median left) (- right median))
|
||
|
|
(begin (helper left (- median 1))
|
||
|
|
(helper (+ median 1) right))
|
||
|
|
(begin (helper (+ median 1) right)
|
||
|
|
(helper left (- median 1)))))
|
||
|
|
v))
|
||
|
|
|
||
|
|
(helper 0 (- (vector-length v) 1)))
|
||
|
|
|
||
|
|
|
||
|
|
(define (partition v left right less?)
|
||
|
|
(let ((mid (vector-ref v right)))
|
||
|
|
|
||
|
|
(define (uploop i)
|
||
|
|
(let ((i (+ i 1)))
|
||
|
|
(if (and (< i right) (less? (vector-ref v i) mid))
|
||
|
|
(uploop i)
|
||
|
|
i)))
|
||
|
|
|
||
|
|
(define (downloop j)
|
||
|
|
(let ((j (- j 1)))
|
||
|
|
(if (and (> j left) (less? mid (vector-ref v j)))
|
||
|
|
(downloop j)
|
||
|
|
j)))
|
||
|
|
|
||
|
|
(define (ploop i j)
|
||
|
|
(let* ((i (uploop i))
|
||
|
|
(j (downloop j)))
|
||
|
|
(let ((tmp (vector-ref v i)))
|
||
|
|
(vector-set! v i (vector-ref v j))
|
||
|
|
(vector-set! v j tmp)
|
||
|
|
(if (< i j)
|
||
|
|
(ploop i j)
|
||
|
|
(begin (vector-set! v j (vector-ref v i))
|
||
|
|
(vector-set! v i (vector-ref v right))
|
||
|
|
(vector-set! v right tmp)
|
||
|
|
i)))))
|
||
|
|
|
||
|
|
(ploop (- left 1) right)))
|
||
|
|
|
||
|
|
; minimal standard random number generator
|
||
|
|
; 32 bit integer version
|
||
|
|
; cacm 31 10, oct 88
|
||
|
|
;
|
||
|
|
|
||
|
|
(define *seed* (list 1))
|
||
|
|
|
||
|
|
(define (srand seed)
|
||
|
|
(set-car! *seed* seed))
|
||
|
|
|
||
|
|
(define (rand)
|
||
|
|
(let* ((hi (quotient (car *seed*) 127773))
|
||
|
|
(lo (modulo (car *seed*) 127773))
|
||
|
|
(test (- (* 16807 lo) (* 2836 hi))))
|
||
|
|
(if (> test 0)
|
||
|
|
(set-car! *seed* test)
|
||
|
|
(set-car! *seed* (+ test 2147483647)))
|
||
|
|
(car *seed*)))
|
||
|
|
|
||
|
|
;; return a random number in the interval [0,n)
|
||
|
|
(define random
|
||
|
|
(lambda (n)
|
||
|
|
(modulo (abs (rand)) n)))
|
||
|
|
|
||
|
|
|
||
|
|
(define (quicksort-benchmark)
|
||
|
|
(let* ((n 30000)
|
||
|
|
(v (make-vector n)))
|
||
|
|
(do ((i 0 (+ i 1)))
|
||
|
|
((= i n))
|
||
|
|
(vector-set! v i (random 4000)))
|
||
|
|
(quick-1 v (lambda (x y) (< x y)))))
|
||
|
|
|
||
|
|
(define (main . args)
|
||
|
|
(run-benchmark
|
||
|
|
"quicksort30"
|
||
|
|
quicksort-iters
|
||
|
|
quicksort-benchmark
|
||
|
|
(lambda (v)
|
||
|
|
(call-with-current-continuation
|
||
|
|
(lambda (return)
|
||
|
|
(do ((i 1 (+ i 1)))
|
||
|
|
((= i (vector-length v))
|
||
|
|
#t)
|
||
|
|
(if (not (<= (vector-ref v (- i 1))
|
||
|
|
(vector-ref v i)))
|
||
|
|
(return #f))))))))
|