I'm partially through chapter 2 of PP, so I thought that I'd add something to this:

Since your common array is going to have 1000 values in it, you may want to define you 1000th value before you start adding stuff to the array, in order to speed up execution time.

my @arr();
$arr[999] = '';
# or perhaps: $#arr = 999;

#... insert code suggested by other perlmonks here
[download]

I'm not sure if 1000 entries on an array is enough to get a speed boost from predefining it's length, but it likely would...

Also, consider compiling to bytecode or doing a memory dump and saving it as an executable file (if it doesn't have to travel across operating systems).

Take care,
Dave.

"For fate which has ordained that there shall be no friendship among the evil has also ordained that there shall ever be friendship among the good." - Plato / Socrates