use 5.012;
my @gilligan=qw(red_shirt hat lucky_socks water_bottle);
&check_required items ("gilligan",@gilligan);

sub check_required items {

$who=shift;
%whos_items=map {$_,1} @_;

@required=qw(preserver sunscreen water_bottle jacket);

for my $item(@required){
unless($whos_items{$item}){

print "$who is missing $item.\n";
}
}
}