[r6rs-discuss] [Formal] Add (sort) and (vector-sort!) procedures

From: Marcin 'Qrczak' Kowalczyk <qrczak>
Date: Mon Oct 2 18:24:42 2006

Eli Barzilay <eli_at_barzilay.org> writes:

> (sort file-names
> (lambda (f1 f2) (< (file-date f1) (file-date f2))))
>
> and
>
> (map cdr
> (sort (map (lambda (f) (cons (file-date f) f)) file-names)
> (lambda (p1) (< (car p1) (car p2)))))
>
> The scond version is doing half the number of FS accesses.

Not half the number but 2*log(N) times less, where N is the number of
elements to be sorted, assuming sorting takes N*log(N) comparisons.

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak_at_knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/

Received on Mon Oct 02 2006 - 18:24:31 UTC