smallest{
 my ($dir,$arr_ref)=@_;
 my %sc; #Cache of file sizes;
 return +(sort {$sc{$a}||=-s $a;
                       $sc{$b}||=-s $b;
                       $sc{$a} <=> $sc{$b}
                       } map { "$dir/$_" } @$arr_ref)[0];
}