Avidity Software

A while back my boss asked us to complete the Morris puzzle for fun. What's the Morris puzzle you ask?

What's the next sequence in this set?

1
11
21
1211
111221

After figuring it out, I couldn't help but want to write a solution in perl. Below is a Perl script that will carry out the progression to 16 lines. Note, this was written to be terse, not readable.

$s = '1';

BLOCK: {
     print "$s\n";

     exit() if ( length( $s ) > 100 );
     
     @nums = split( //, $s );
     @uniq = ();
     $tmp = ();
     
     foreach my $num ( @nums ){
          push( @uniq, $num ) if ( $num != $uniq[-1] );
     }
     
     foreach my $num ( @uniq ) {
          $s =~ s/^($num+)//;
          $tmp .= ( length( $1 ) . $num );
     }
     
     $s = $tmp;
     goto BLOCK;
}