gen( 5, 50, 0, sub { print "@_\n" } );

sub gen
{
	my( $cols, $max, $used, $found, @vec ) = @_;
	return $found->( @vec, $max-$used ) if $cols == 1;
	gen( $cols-1, $max, $used+$_, $found, @vec, $_ )
		for 0 .. $max-$used;
}