% 
% Global constraint k_same in MiniZinc.
% 
% From Global Constraint Catalogue
% http://www.emn.fr/x-info/sdemasse/gccat/sec4.155.html
% """
% k_same​(SETS)
% 
% Purpose
%
% Given |SETS| sets, each containing the same number of domain variables, 
% the k_same constraint enforces that the multisets of values assigned to each set are all identical.
%
% Example
%     (
%     <
%     set-<1, 9, 1, 5, 2, 1>,
%     set-<9, 1, 1, 1, 2, 5>,
%     set-<5, 2, 1, 1, 9, 1>
%     >
%     )
%
% The k_same constraint holds since:
%
%  * The first and second collections of variables are assigned to the 
%     same multiset.
%
%  * The second and third collections of variables are also assigned to 
%    the same multiset.
% """


% Note: MiniZinc don't support multisets, so we use arrays instead.

% This MiniZinc model was created by Hakan Kjellerstrand, hakank@bonetmail.com
% See also my MiniZinc page: http://www.hakank.org/minizinc
%

include "globals.mzn";

int: n = 3;
int: m = 6;
array[1..n, 1..m] of var 1..9: x;



solve :: int_search([x[i,j] | i in 1..n, j in 1..m], "anti_first_fail", "indomain", "complete") satisfy;

constraint
     
   x = array2d(1..n, 1..m, [
      1,9,1,5,2,1,
      %_,9,_,_,_,1, % test
      9,1,1,1,2,5,
      5,2,1,1,9,1
  ])

   /\
   forall(i in 2..n) (
      let {
         int: low = lb(x),
         int: up  = ub(x),
         array[low..up] of var 0..up: i_gcc,
         array[low..up] of var 0..up: j_gcc
      }
      in
      global_cardinality([x[i,k] | k in 1..m], i_gcc) 
      /\
      global_cardinality([x[i-1,k] | k in 1..m], j_gcc)
      /\
      forall(k in low..up) (
         i_gcc[k] = j_gcc[k]
      )
   )
;

output [
    if j = 1 then "\n" else " " endif ++
      show(x[i,j])
   | i in 1..n, j in 1..m
];