use strict;
use warnings;
use Set::Scalar;
use List::Compare;
use Benchmark qw/cmpthese/;

my @arr_1 = 0 .. 8e3;
my @arr_2 = 2e3 .. 1e4;

sub setScalar {
	my $s1   = Set::Scalar->new(@arr_1);
	my $s2   = Set::Scalar->new(@arr_2);
	my $diff = $s1->difference($s2);
}

sub listCompare {
	my $lc = List::Compare->new( \@arr_1, \@arr_2 );
	my @diff = $lc->get_Lonly;
}

sub OPdiff {
	my %diff3;
	@diff3{@arr_1} = @arr_1;
	delete @diff3{@arr_2};
	my @diff = ( keys %diff3 );
}

sub OPdiffModified {
	my %diff3;
	@diff3{@arr_1} = ();
	delete @diff3{@arr_2};
	my @diff = ( keys %diff3 );
}

sub OPdiff_undef {
	my %diff3;
	undef @diff3{@arr_1};
	delete @diff3{@arr_2};
	my @diff = ( keys %diff3 );
}

sub using_vec {
	my $vec = '';
	vec( $vec, $_, 1 ) = 1 for @arr_2;
	my @diff = grep !vec( $vec, $_, 1 ), @arr_1;
}

sub hash_grep {
	my %arr_2_hash;
	undef @arr_2_hash{@arr_2};
	my @diff = grep !exists $arr_2_hash{$_}, @arr_1;
}

cmpthese(
	-5,
	{
		setScalar      => sub { setScalar() },
		listCompare    => sub { listCompare() },
		OPdiff         => sub { OPdiff() },
		OPdiffModified => sub { OPdiffModified() },
		OPdiff_undef   => sub { OPdiff_undef() },
		using_vec      => sub { using_vec() },
		hash_grep      => sub { hash_grep() }
	}
);

##</code><code>##

                 Rate setScalar listCompare using_vec OPdiff OPdiffModified hash_grep OPdiff_undef
setScalar      7.94/s        --        -72%      -98%   -98%           -98%      -98%         -99%
listCompare    28.1/s      254%          --      -92%   -93%           -94%      -94%         -96%
using_vec       349/s     4289%       1139%        --    -7%           -27%      -32%         -47%
OPdiff          375/s     4623%       1233%        8%     --           -22%      -26%         -42%
OPdiffModified  478/s     5919%       1599%       37%    27%             --       -6%         -27%
hash_grep       510/s     6317%       1712%       46%    36%             7%        --         -22%
OPdiff_undef    652/s     8105%       2217%       87%    74%            36%       28%           --            --