Like with most things perl, there's more then one way to do it. You could use Quantum::Superpositions, or (sort @array)[-1], or you could do somthing more reasonable, like

my $max=$array[0];
foreach (@array) {
 $max=$_ if ($_>$max)
}
[download]

Or you could use List::Util::max (which is included with perl >=5.8.0)