use strict;

my @orig = ( qw(a a b b c 0 c d d u u), 
            (undef, undef, 'blink', 'blink'), 
             qw(0 0 v v w w a a a b b b c c c)
            );
my @list;
nodupes (\@orig, \@list);
print join ' ', @list, "\n";

sub nodupes {
    my ($ar1, $ar2) = @_;
    my $p;
    push @$ar2, grep{$_ ne 'aardvark'} 
                map{defined $_ ? $_ : 'undef'} 
                map { $p ne $_ ? $p = $_ : 'aardvark' } 
         @$ar1;
}
__END__

Prints --> a b c 0 c d u undef blink 0 v w a b c

##</code><code>##

perl -e "@list = grep{$_ ne 'aardvark'} 
                 map{defined $_ ? $_ : 'undef'} 
                 map{$p ne $_ ? $p = $_ : 'aardvark'} 
        (qw(a a b b c 0 c u u), (undef, undef), qw(0 0 v v w w)); 
print join ' ', @list;"

Prints --> a b c 0 c u undef 0 v w

##</code><code>##

use strict;
sub nodupes {
    my $p;
    return grep{ $_ ne '~~' } map { $p ne $_ ? $p = $_ : '~~'  } @_;
}

my @orig = ( qw(a a b b c 0 c d d u u),
            (undef, undef, 'blink', 'blink'),
             qw(0 0 v v "0" "0" "0" w w a a a b b b c c c)
            );

my @new = nodupes @orig;
print join ' ', @new, "\n";

__END__
Prints --> a b c 0 c d u  blink 0 v "0" w a b c
                        ^^
     There's an undef between these two spaces.