use strict;

my @keyset = qw/this repeat that repeat/;
my @valset = qw/jerry george elaine kramer/;

print "\@keyset has ",
      hasdup(\@keyset) ? "duplicates (warning)"
                       : "no duplicates", "\n";
print "\@valset has ",
      hasdup(\@valset) ? "duplicates"
                       : "no duplicates", "\n";

sub hasdup
{
    my $array = shift;

    # get the index of the elements in the uniq array
    my $last = $#{[keys %{{ map {$_ => 1} @$array }}]};

    return $#{@$array} != $last;
}