#! perl -slw
use strict;
use Memoize;
use Benchmark::Timer;
use List::Util qw[ sum ];

BEGIN{ @ARGV  = map{ eval }@ARGV }

sub Cnr{
    my( $n, @r ) = shift;
    return [] unless $n--;
    for my $x ( 0 .. ($#_ - $n) ) {
        push @r, map{ 
        	[ $_[$x], @$_ ] 
        } Cnr( $n, @_[ ($x + 1) .. $#_ ] );
    }
    return @r;
}

sub sums{ 
	my( $required, @values ) = @_;
	return grep{
		sum( @$_ ) == $required
		? $_
		: ()
	} map{ 
		Cnr( $_, grep $_ < $required, @values ) 
	} 1 .. $#values;
}

my $T = new Benchmark::Timer;

#$T->start( 'raw' );
#my @sums = sums( @ARGV );
#$T->stop( 'raw' );

$T->start( 'memoized' );
memoize( 'Cnr' );
my @sums2 = sums( @ARGV );
$T->stop( 'memoized' );

$T->report;

print "@$_" for @sums2;