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Groups > comp.lang.c > #167121
| From | antispam@math.uni.wroc.pl |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: How to optimize this search? |
| Date | 2022-08-22 19:30 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <te0lgm$7fh$1@gioia.aioe.org> (permalink) |
| References | <d8294420-7b45-4344-b9eb-0ad867850ec6n@googlegroups.com> <chine.bleu-825230.08435922082022@news.eternal-september.org> <9ddfe85a-a07f-4d99-aab1-946f678a1f07n@googlegroups.com> |
Thiago Adams <thiago.adams@gmail.com> wrote:
> On Monday, August 22, 2022 at 12:44:22 PM UTC-3, Siri Cruise wrote:
> > In article
> > <d8294420-7b45-4344...@googlegroups.com>,
> > Thiago Adams <thiago...@gmail.com> wrote:
> >
> > > Given a c string I need to return as fast as possible the pair (if exist) of
> > > the corresponding keyword_pair.
> > You can build a Finite State Automaton.
>
> Yes.. I am thinking exactly like that. But at some point
> we need to map like char -> state then it is the same
> switch problem. How to given char how to find the state in a fast way?
You need map (state, char) -> state, that is pair state, char to new
state. Easily done with two dimensional array:
int s = 1; /* could use symbolic name here */
unsigned char cp;
while (s && (c = *cp++)) {
s = transition[s][c];
}
After loop test if c = 0, if yes all input string was used, if no
it was rejected before end. If c = 0 thes is s is accepting (single
table lookup), if yes it gives result, if no mens not found.
In your case you will have few hundred cases, so table will be
largish. Traditionally table is compressed by so called comb
vector method. Namely, most entris are "empty", that is they
do not correspond to valid transitions (encoded by 0 above).
In comb vector method we put transitions in one dimensional
array, with some offset for each state. Offsets are chosen
so that _valid_ transitions are in different places. This
can be done in greedy way: use offset zero for first state.
For state n start from zero offset and shift it to find
place with no overlap with previous vectors. Repeat as long
as needed.
Comb vector methods needs two additional arrays: one for
offsets (indexed by states) and another one to check if
transition correspond to current state.
With compressed tables automaton needs more instructions
per transition. OTOH smaller tables means less cache
misses, so may win despite executiong more instructions.
--
Waldek Hebisch
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How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 07:17 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 07:34 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-22 16:17 +0000
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:24 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:38 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-22 17:03 +0000
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 14:58 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 05:02 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 17:50 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-23 16:58 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 19:21 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 09:46 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 20:06 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-23 23:39 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-24 11:20 +0300
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-25 00:52 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 23:23 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-26 01:38 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-26 00:55 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-26 12:02 +0300
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-26 04:10 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 10:47 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-22 18:10 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 15:22 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-22 15:37 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 16:28 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-23 01:18 +0100
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 18:01 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-23 00:07 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 18:12 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-23 01:54 +0000
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-23 08:50 +0200
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 04:18 -0700
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-23 15:50 +0200
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 18:51 +0000
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:34 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:14 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 17:33 +0100
Re: How to optimize this search? Siri Cruise <chine.bleu@yahoo.com> - 2022-08-22 08:44 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:53 +0100
Re: How to optimize this search? Siri Cruise <chine.bleu@yahoo.com> - 2022-08-22 09:29 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 17:36 +0100
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:53 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:11 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 19:30 +0000
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 14:19 -0700
Re: How to optimize this search? Öö Tiib <ootiib@hot.ee> - 2022-08-22 14:36 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 22:49 +0000
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 05:13 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 15:55 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 16:36 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 17:42 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 18:36 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 03:34 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 04:40 -0700
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-24 09:30 +0200
Re: How to optimize this search? William Ahern <william@25thandClement.com> - 2022-08-24 12:36 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 17:51 +0200
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:55 +0100
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:14 +0200
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:15 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:28 +0200
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:34 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:35 +0200
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:45 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:51 +0200
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 17:53 +0300
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 10:20 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 10:53 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 23:31 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 17:04 -0700
Re: How to optimize this search? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-08-23 09:50 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 10:07 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 11:28 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 12:17 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 13:16 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 13:18 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 13:23 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 13:40 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 16:26 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 16:50 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 17:26 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-23 23:54 +0000
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 17:16 -0700
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-24 09:43 +0200
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 04:03 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-24 14:15 +0000
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 13:28 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 06:25 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 06:50 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 15:19 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 09:46 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 20:40 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 10:08 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 20:42 +0100
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 07:31 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-25 01:04 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 16:43 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 16:54 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 17:08 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-26 01:47 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-26 05:40 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-26 06:29 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-26 14:05 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 06:45 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 13:01 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-25 01:17 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 23:38 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-25 11:29 +0300
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-25 11:33 +0300
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