my @p = (1,1,1,1,1,2,2,2,3,3,4,5,6);
my @q = (1,2,3,4,5,6 );
# my @p = (43, 43, 44);
# my @q = (43, 43);

my %q;
$q{$_}++ for @q;

my @r = grep {
    --$q{$_} < 0;
} @p;

print join (',', @r), "\n";