/* 

  Global constraint atleast_nvalue in Picat.

  From Global Constraint Catalogue
  http://www.emn.fr/x-info/sdemasse/gccat/Catleast_nvalue.html
  """
  The number of distinct values taken by the variables of the collection 
  VARIABLES is greater than or equal to NVAL.
  
  Example
   (2, <3, 1, 7, 1, 6>)
  
  The atleast_nvalue constraint holds since the collection
  <3, 1, 7, 1, 6> involves at least 2 distinct values (i.e., in 
  fact 4 distinct values).
  """

  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 :: 1..7, 
  NVal :: 1..N,

  X = [3,1,7,1,6],
  atleast_nvalue(NVal, X),
  NVal #= 2,

  Vars = X ++ [NVal],
  solve(Vars),

  println(x=X),
  println(nval=NVal),
  nl,

  fail,
  
  nl.

go => true.

atleast_nvalue(NVal, X) =>
  nvalue(NVal2,X),
  NVal2 #>= NVal.