use strict;

my (@listA, @listB);
$listA[0] = [qw(1 foo bar)];
$listB[0] = [qw(1 bar baz)];

my %hash = map { $_ => 1 } @{$listA[0]};
my @c = grep {! exists $hash{$_}} @{$listB[0]};

print "$_\n" foreach (@c);