/* 

  Global constraint cardinality_atmost in Picat.

  From Global Constraint Catalogue
  http://www.emn.fr/x-info/sdemasse/gccat/Ccardinality_atmost.html
  """
  ATMOST is the maximum number of occurrences of each value of VALUES within 
  the variables of the collection VARIABLES.
  
  Example
  (
   2, <2, 1, 7, 1, 2>,
      <5, 7, 2, 9>
  )
  
  In this example, values 5, 7, 2 and 9 occur respectively 0, 1, 2 and 0 times 
  within the collection <2, 1, 7, 1, 2>. As a consequence, the 
  cardinality_atmost constraint holds since its first argument ATMOST 
  is assigned to the maximum number of occurrences 2.
  """


  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,
  M = 4,
  
  Variables = new_list(N),
  Variables :: 1..9,
  Values = new_list(M),
  Values :: 1..9,

  NVar :: 0..9,

  Variables = [2,1,7,1,2],
  Values = [5,7,2,9],
  % NVar #= 2,

  cardinality_atmost(NVar, Variables, Values),

  Vars = Variables ++ Values ++ [NVar],
  solve(Vars),

  println(variables=Variables),
  println(values=Values),
  println(nvar=NVar),
  nl,

  fail,
  
  nl.

go => true.


cardinality_atmost(NVar, Variables, Values) =>
   foreach(I in 1..Values.len)
     sum([Values[I] #= Variables[J] : J in 1..Variables.len]) #<= NVar
   end.