/* 

  Global constraint all_same_except_0 in Picat.

  all_same_except_0(X) ensures that all values > 0 in the list X are the same.
  Note that it is not necessary that there are any 0s in the list.

  For a "real world" example of this constraint, see
  http://hakank.org/picat/coins_41_58.pi

  This Picat model was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/

import cp.


main => go.

go ?=>
  N = 5,
  X = new_list(N),
  X :: 0..N,

  all_same_except_0(X),

  solve(X),
  println(X),
  fail,
  
  nl.

go => true.


all_same_except_0(X) =>
  N = X.len,
  foreach(I in 1..N, J in 1..N)
     X[I] #= X[J] 
     #\/ 
     X[I] #= 0 
     #\/
     X[J] #= 0
  end.