use Data::Dumper
my(@list_a)=(qw(a b c d e f g));
my(@list_b)=(qw(a c e g h j k));
my(%just_a,%just_b,%both);

@just_a{@list_a}=(); delete @just_a{@list_b};

@just_b{@list_b}=(); delete @just_b{@list_a};

@both{@list_a}=(); delete @both{keys %just_a};

print Data::Dumper->Dump([
      [keys %just_a],[keys %just_b],[keys %both]
  ],
  [qw/just_a just_b both/]
)

##</code><code>##

$just_a = [
            'b',
            'd',
            'f'
          ];
$just_b = [
            'k',
            'h',
            'j'
          ];
$both = [
          'e',
          'c',
          'a',
          'g'
        ];