sub bin {
  my ($size, @set) = @_;
  my $best = [];
  my @bins;

  _bin($size, \@set, \@bins, 0, $best);
  print "BEST: <@{[ map qq{[@$_]}, @$best ]}>\n";
}


sub _bin {
  my ($size, $set, $bins, $i, $best) = @_;

  if (@$set == 0) {
    @$best = map [@$_], @$bins if @$bins > @$best;
    return;
  }

  my $rem = $size - sum($bins->[$i]);

  for (sort { $set->[$b] <=> $set->[$a] } grep { $set->[$_] <= $rem } 0 .. $#$set) {
    my $n = splice @$set, $_, 1;
    push @{ $bins->[$i] }, $n;
    _bin($size, $set, $bins, (sum($bins->[$i]) == $size) ? $i+1 : $i, $best);
    _bin($size, $set, $bins, $i+1, $best) if 0 == grep { $set->[$_] <= ($rem-$n) } 0 .. $#$set;
    pop @{ $bins->[$i] };
    pop @$bins if @{ $bins->[$i] } == 0;
    splice @$set, $_, 0, $n;
  }
}


sub sum {
  my $s = 0;
  $s += $_ for @{ $_[0] };
  $s;
}