35 chars:
sub seq{!grep{$_[0]!~/\G.*?$_/g}split//,pop}
update: And now what everyone's been waiting for:
The longest word(s) with all letters in alphabetical order:
solaris /usr/dict/words:  almost biopsy
linux    /usr/dict/words:  abhors almost begins biopsy chintz
The longest word(s) with all letters in reverse alphabetical order:
sol:  sponge
lun:  sponged wronged
The word(s) with the most letters in alphabetical order:
sol: condemnatory 8
lun: administratively antidisestablishmentarianism behavioristic
        demonstratively incomprehensibility 8
shortest: behavioristic
update oopsdate: Removed words w/ most letters in order. It was wrong, though noone remarked on it (if you were being polite, thank you). Will re-post when, if I get it right. Anyone else care to try?
update 3: maybe the above are right now. The code is:
sub seq{
my @x=split"",pop;
my $s=pop;
my $cc=0;
for my $k (0..$#x-1) {
$c = seq1($cc, $s, @x[$k..$#x]);
$cc = ($c, $cc)[ $c < $cc ]
}
$cc
}
sub seq1 {
my($cc, $s, @x) = @_;
my $c=pos($s)=0;
my $op=0; my $cy=0;
for my $k (0..$#x) {
$s =~ /$x[$k]/gc or next;
if ($cc <= @x - $k) { # what if we skip this char?
my $cx = $c + seq1( $cy, substr($s, $op), @x[$k+1 .. $#x]);
$cy = ($cx, $cy)[$cx < $cy];
}
$op = pos($s);
$c++;
}
$c = ($cy, $c)[ $cy < $c ];
}
Update the last:  Actually, this one can be done in 27 chars:
sub seq{!grep$_[0]!~/$_/g,pop=~/./g}
  ...or 30 with provision for strange_chars/newlines:
sub seq{!grep$_[0]!~/\Q$_/g,pop=~/./gs}
But see my trimming of
japhy's
above.
 
p
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
|
For: |
|
Use: |
| & | | & |
| < | | < |
| > | | > |
| [ | | [ |
| ] | | ] |
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.