my %tmp = map { $_ => 1} @foo;
my @uniq_foo = sort keys %tmp;

##</code><code>##

my @uniq_foo = sort keys %{ {map { $_ => 1} @foo} };

##</code><code>##

my %uniq = map {
    my %tmp = map { $_ => 1} @$_;
    $_ => [sort keys %tmp];
} keys %arrays;

##</code><code>##

my %uniq = map {
    $_ => [sort keys %{ {map { $_ => 1} @$_} }];
} keys %arrays;

##</code><code>##

my %uniq = map {
    my %saw;
    $_ => [map !$saw{$_}++, @$_];
} keys %arrays;

##</code><code>##

my %uniq = map { $_ => [uniq @$_] } keys %arrays;