/* 

  Global constraint lex_greater in Picat.

  From Global Constraint Catalogue
  http://www.emn.fr/x-info/sdemasse/gccat/Clex_greater.html
  """
  lex_greater(VECTOR1, VECTOR2)
  
  Purpose

  VECTOR1 is lexicographically strictly greater than VECTOR2. Given two 
  vectors, X and Y of n components, 〈X0, ..., Xn−1〉 and 〈Y0, ...,Yn−1〉, 
  X is lexicographically strictly greater than Y if and only if X0> Y0 
  or X0=Y0 and 〈X1, ..., Xn−1〉 is lexicographically strictly greater 
  than 〈Y1, ..., Yn−1〉.
  
  Example
    (
    <5, 2, 7, 1>,
    <5, 2, 6, 2>
    )
  
  The lex_greater constraint holds since VECTOR1=<5, 2, 7, 1> is 
  lexicographically strictly greater than VECTOR2=<5, 2, 6, 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 = 4,
  Vector1 = new_list(N),
  Vector1 :: 1..7,
  Vector2 = new_list(N),
  Vector2 :: 1..7,

  Vector1 = [5,2,7,1],
  % Vector2 = [5,2,6,2],

  lex_greater(Vector1, Vector2),

  Vars = Vector1 ++ Vector2,
  solve(Vars),

  println(vector1=Vector1),
  println(vector2=Vector2),
  nl,
  fail,

  nl.

go => true.


lex_greater(X, Y) =>
  lex_lt(Y, X).