use Modern::Perl;
use Regexp::Assemble;

# load the arrays
my @cg = ( 1, 5, 12, 3 );
my @gl = map { int( rand 20 ) + 1 } ( 1 .. 100 );
my @csta = map { chr( $_ + 64 ) } @gl;
say "@gl\n@csta";    # for debug purposes only

# assemble the regex
my $ra = Regexp::Assemble->new;
$ra->add(@cg)->anchor_word(1)->re;
say $ra->as_string;    # for debug purposes only

# find the matches
for my $idx ( keys @gl ) {
    say "$idx: $gl[$idx] : $csta[$idx]" if ( $gl[$idx] =~ m/$ra/ );
}