pt <> wrote in comp.lang.perl.misc:
> wrote:
> > "pt" <> wrote:
> > > I'm trying to figure out a fast, efficient way to represent a single,
> > > 52 card deck plus player & community card hands for a Texas holdem
> > > poker simulation. I need to be able to detect hand classifications
> > > (X-of-a-kind, flush, straight, etc) and winning hands. I was thinking
> > > of using a string & RE. I was assuming (yea, I know...) that a "hand"
> > > data structure based on hash or array would slow things down.
> >
> > Complicated regexes can get pretty slow, too. Plus your probably going to
> > need to go into arrays or hashes for some things, anyway.
>
> I was hoping a regex would be faster than hash/array lookups, but
> that's just based on ignorance on my part.
>
> >
> > > Here's
> > > my string-based hand idea:
> > > Cards are represented by 2 chars: rank & suit. 2-9,T,J,Q,K,A
> >
> > That would need a custom sorting routine. I'd represent them by
> > some bytes already in value order (Can A be low in Texas Hold-em? That
> > would throw a spanner in the works)
>
> Yep. Consider that spanner thrown.
>
> >
> >
> > > and
> > > DCHS. 5 of Diamonds would be "5D". Player's hand (as a string) would
> > > be concatenated with community cards to form a searchable string :
> > > "5DTH2C3S4H". Pair detection regex would be /(.)[DCHS].*\1/
> >
> > How about a full house?
>
> More interesting. The "3-of-a-kind" regex AND the "pair" regex, where
> the "pair" rank isn't the same as the 3OAK rank:
> return $Hand =~ /(.)[DCHS].*\1[DCHS].*\1[DCSC]/ &&
> ($Hand =~ /([^$1])[DCHS].*\1[DCHS]/) ;
>
>
> >
> > > This makes straight detection hard without sorting, and I'm trying to
> > > make this fast.
> >
> > If speed is the overriding concern, I'd do it in C, not Perl. (or maybe C
> > and Perl).
>
> Ack! Haven't done C in a while.
>
> Maybe a radix sort ..... hmmmm.
Instead of an explicit radix sort you could consider a bit table
representation of hands. Use (0 .. 51) to represent the individual
cards. For list @cards (a list of integers in that range) construct
a bit vector:
my $hand = "\0" x 7;
vec( $hand, $_, 1) = 1 for @cards;
That gives you a unique representation for each hand with no explicit
sorting (this is your radix sort). Further, you can prepare masks that
indicate all cards of one suit, or of one rank, or other combinations
that may be useful. Thus
my $kings = $hand & $suit_mask{ king};
would leave only the bits for kings that were set in the original
hand. A fast way of counting bits is documented in unpack:
my $n_of_kings = unpack '%32b*', $kings;
would give you their number.
I don't know how this would work out in a full analysis of a poker hand.
Your mention of radix sort made me think of it. (Code untested)
Anno
--
$_='Just another Perl hacker'; print +( join( '', map { eval $_; $@ }
'use warnings FATAL => "all"; printf "%-1s", "\n"', 'use strict; a',
'use warnings FATAL => "all"; "@x"', '1->m') =~
m|${ s/(.)/($1).*/g; \ $_ }|is),',';
--
$_='Just another Perl hacker'; print +( join( '', map { eval $_; $@ }
'use warnings FATAL => "all"; printf "%-1s", "\n"', 'use strict; a',
'use warnings FATAL => "all"; "@x"', '1->m') =~
m|${ s/(.)/($1).*/g; \ $_ }|is),',';
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