Without understanding what your code does, I whittled 100 strokes off its length by performing some routine golfic shortenings:

@z=(sub{$c=pop;$x{$"}=$C{$"}=$";$x{$_}or$x{$C{$k}=$_}=$k=chr
ord(A)+($a+++$c)%26for pop=~/./g,a..z},sub{$h=pop;$r.=$$h{$_}for
pop=~/./g;$r});$z[0]->(thequickbrownfoxjumpsoverthelazydogs,10);
print$z[1]->('ZOCK FWUKLMT BMTE LFQR',\%C).$/
[download]

Update: whittled a further 10 strokes.

Wonderful. Is there a "routine golf shortenings" node?

---

I humbly seek wisdom.

<shameless plug>
There's a number of tips and techniques listed in Perl Golf 101 as well as in the comments to that node.
</shameless plug>


--chargrill

---

s**lil*;  $*=join'',sort split q**;  s;.*;grr; &&s+(.(.)).+$2$1+; $; =
qq-$_-;s,.*,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$*,$/)
[download]

My first clue is to explain ACA in the post. It's probably not very helpful; just a nudge in a direction. Here's the link:

My next clue is somethign most here could do themselves, but I just learned it this week (from reading PerlMonks!). Here's the perl -MO=Deparse output (this is without eyepopslikeamosquito's reduction):

@ca = (sub {
    @kp = split(//, shift @_, 0);
    $c = shift @_;
    $p2{' '} = ' ';
    $C2{' '} = ' ';
    foreach $_ (@kp, ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'
+, 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x
+', 'y', 'z')) {
        if (not exists $p2{$_}) {
            $k = chr 65 + ($a++ + $c) % 26;
            $p2{$_} = $k;
            $C2{$k} = $_;
        }
    }
}
, sub {
    $t = shift @_;
    $h = shift @_;
    foreach $_ (split(//, $t, 0)) {
        $r = $r . $$h{$_};
    }
    return $r;
}
);
$ca[0]->('thequickbrownfoxjumpsoverthelazydogs', 10);
print $ca[1]->('ZOCK FWUKLMT BMTE LFQR', \%C2) . "\n";
[download]

My next clue is to comment my variables. This is a big leap and probably a give away. I wish I had better intermediate clues for ya.

ok, here's what I'm doing: