%alphabet = (%alphabet, map { $_ => 1 } @chars);

##</code><code>##

@alphabet{@chars} = (); # No need to set values to 1 as you only ever use keys

##</code><code>##


    if(defined $sorted{$characters}) {
        push @{$sorted{$characters}}, $line;
    }
    else {
        $sorted{$characters} = [$line];
    }

##</code><code>##

push @{$sorted{$characters}}, $line;

##</code><code>##

    foreach (my $pos2 = 0; $pos2 < $count; $pos2++) {
        next if $pos2 < $pos1;

##</code><code>##

for (my $pos2 = $pos1; $pos2 < $count; $pos2++) {