my $str = shift || "17:43:33:21:23:19:27:6";
my @a1 = ();
my @a2 = ();
my @a = split /:/, $str;
while ( my ( $p, $ad ) = splice @a, 0, 2 ) {
    push @a1, map {$ad} (1..$p);
    push @a2, ($ad) x $p;
}

use Benchmark 'cmpthese';

print "Accessing element 0:\n";
cmpthese(-1, { made_by_map => sub { $a1[0]; },
               made_by_x   => sub { $a2[0]; } });

print "\nAccessing element 50:\n";
cmpthese(-1, { made_by_map => sub { $a1[50]; },
               made_by_x   => sub { $a2[50]; } });

print "\nAccessing element 99:\n";
cmpthese(-1, { made_by_map => sub { $a1[99]; },
               made_by_x   => sub { $a2[99]; } });

print "\nAccessing random element:\n";
cmpthese(-1, { made_by_map => sub { $a1[rand 100]; },
               made_by_x   => sub { $a2[rand 100]; } });