#!/perl -w 
use strict;
use Benchmark;

timethese(200000, {
    'single' => sub {
    					my $dna = "NNNNATCGNNNTCGANNN";
    					$dna =~ s/^N*(.*?)N*$/$1/;
    				},
    'twin'   => sub {
    					my $dna = "NNNNATCGNNNTCGANNN";
    					$dna =~ s/^N*//;
    					$dna =~ s/N*$//;
    				},
});


__OUTPUT__
Benchmark: timing 200000 iterations of single, twin...
    single:  3 wallclock secs ( 2.95 usr +  0.00 sys =  2.95 CPU) @ 67704.81/s (n=200000)
      twin:  1 wallclock secs ( 0.83 usr +  0.00 sys =  0.83 CPU) @ 240963.86/s (n=200000)