@array1 = (1,1,2,3,3,4);
#unique
print unique(@array1);

#not
print unique(\@array1);

sub unique{
my (%seen, $array);
($array)=@_;
if(@$array){return grep{$seen{$_} ++} @$array;}
else{return grep{ ! $seen{$_} ++} @_;}
}