my @a = (0 .. 25);
sub c{$_[0] % 3 == 0 }
sub S{my@t;push@{$t[c($_)]},$_ for@_;@t}
my($l,$r)=S(@a);
print "@$l\n";
print "@$r\n";

##</code><code>##

my @a = (0 .. 25);
sub c{$_[0] % 3 == 0 }
sub S{my@t;push@{$t[$_[0]($_)]},$_ for@{$_[1]};@t}
my($l,$r)=S(\&c,\@a);
print "@$l\n";
print "@$r\n";