use strict;
use warnings;

search(["bobcat", "boomerang", "beer", "bat"], ["-bo"], ["b"]);

sub search {
   my ($data, $negative_criteria, $positive_criteria )= @_; 
   my $re="^(?!" . join("|", map{ s/^-//;$_ }@$negative_criteria) . ")"
           . join "|", @$positive_criteria;
   $re=qr|$re|;
   my @results = grep { m/$re/ } @$data;
   for (0..$#results){
     print  $_+1 . " - $results[$_]\n";
   }
   return \@results;
}