#! perl
use strict;
use warnings;
use constant MIN_MATCHES => 5;

my %sequ =
(
    1 => 'abcXXXXXef',
    2 => 'abcYYYYYYef',
    3 => 'abZZZZef',
);

my $match_at_least = MIN_MATCHES - 1;

for my $k (1 .. 3)
{
    if (my @matches = $sequ{$k} =~ m/(([A-Z])\g2{$match_at_least,})/)
    {
        print "Match: $matches[1] in $matches[0] \n";
    }
}

##</code><code>##

16:47 >perl 1069_SoPW.pl
Match: X in XXXXX
Match: Y in YYYYYY

16:47 >