From: John Carr <jfc@MIT.EDU>
To: Brian Hurt <brian.hurt@qlogic.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] tree walking with... specular rec functions? what else?
Date: Mon, 12 May 2003 08:57:05 -0400 [thread overview]
Message-ID: <200305121257.IAA29080@nerd-xing.mit.edu> (raw)
In-Reply-To: Your message of "Fri, 09 May 2003 10:23:20 CDT." <Pine.LNX.4.33.0305090959170.2037-100000@eagle.ancor.com>
I have a minor comment unrelated to the basic algorithm.
> ...
> let rec outer lst =
> if (List.length lst) == 0 then ()
> else outer (inner lst [])
> in
> ...
In general it is better to test for empty rather than compare the size
of a collection to 0. With some collections (including lists) testing
for empty takes constant time but computing size takes linear time.
Instead of
if (List.length lst) == 0 then empty-code else full-code
either of these will be faster:
if lst == [] then empty-code else full-code
(match lst with [] -> empty-code | _ -> full-code)
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next prev parent reply other threads:[~2003-05-12 12:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-09 9:56 Stalkern 2
2003-05-09 15:23 ` Brian Hurt
2003-05-12 12:57 ` John Carr [this message]
2003-05-12 13:35 ` Michal Moskal
2003-05-12 15:06 ` David Brown
2003-05-12 15:24 ` Xavier Leroy
2003-05-11 16:02 ` Xavier Leroy
2003-05-12 6:55 ` Stalkern 2
2003-05-12 10:14 ` Gérard Huet
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