advent_or_day8.mzn

include "globals.mzn";

% Number of items
int: N;

% Bin capacity
int: C;

set of int: ITEMS = 1..N;

% Upper Bound on the number of bins used
int: max_bins = N;
set of int: BINS = 1..max_bins;

array[ITEMS] of int: item_sizes;

% What bin each item goes to
array[ITEMS] of var BINS: item_placement;

var BINS: total_bins;

constraint bin_packing(C, item_placement, item_sizes);

constraint total_bins = max(item_placement);

solve minimize total_bins; 

Results: (1 minute run)

Instance	Gecode	Best
u120_00	49	48
u120_01	49	49
u120_02	46	46
u120_03	49	49
u120_04	50	50
u120_05	48	48
u120_06	48	48
u120_07	50	49
u120_08	51	51
u120_09	47	46
u120_10	52	52
u120_11	49	49
u120_12	49	48
u120_13	49	49
u120_14	50	50
u120_15	48	48
u120_16	52	52
u120_17	53	52
u120_18	49	49
u120_19	50	50