No? Would you care to elaborate? I just retested, and it works fine.

Okay.

sub chain {
    my ($genome,@genome) = @_;
    for ($i..$#genome) {
 ....
[download]

Where is $i set? for $_ ( $i .. $#genome)? and 32 Uninitialised string in eq errors every loop, if the loop had a defined starting place.

sub hash_array {
    my ($genome,@genome) = @_;
    $counts { $genome [$i] . $genome [$i + 1] } ++ for (0..$#genome);
}
[download]

Where does $i come from? <and that's only scratching the surface.

---

Examine what is said, not who speaks.

"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
Hooray!
Wanted!

Ah, you're right. I ran it and saw benchmark numbers that looked right, and so I figured it was fine. I'm sorry. However, it would have been courteous to not have been so vague in your first post; I probably would have bothered to re-look at my code.