use strict;
use warnings;

use Benchmark qw( cmpthese ) ;

use vars qw/$tuplets $template/;

$tuplets = join '', ( 'aaa' .. 'caa' );
$template = join '', 'a3' x ( length( $tuplets ) / 3 );

print "Test string contains ", 
      length( $tuplets ) / 3, 
      " groups.\n\n";

cmpthese( 
    -10, 
    {
        regexp => sub {
            return $tuplets !~ /^(?:.{3})*(.{3})(?:.{3})*\1/;
        },
        hash => sub {
            my %hash;
            @hash{ unpack $template, $tuplets } = ();
            return( 
                length( $tuplets ) / 3 == keys( %hash )
            );
        }
    }
);

##</code><code>##

Test string contains 1353 groups.

          s/iter regexp   hash
regexp      1.15     --   -98%
hash   1.84e-002  6123%     --