alldifferent_except_0.cs

//
// Copyright 2012 Hakan Kjellerstrand
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;
using Google.OrTools.ConstraintSolver;


public class AllDifferentExcept0Test
{

  //
  // Decomposition of alldifferent_except_0
  //
  public static void AllDifferentExcept0(Solver solver, IntVar[] a) {

    int n = a.Length;
    for(int i = 0; i < n; i++) {
      for(int j = 0; j < i; j++) {
        solver.Add((a[i] != 0) * (a[j] != 0) <= (a[i] != a[j]));
      }
    }
  }


  /**
   *
   * Decomposition of alldifferent_except_0
   *
   * See http://www.hakank.org/google_or_tools/map.py
   *
   *
   */
  private static void Solve()
  {
    Solver solver = new Solver("AllDifferentExcept0");

    //
    // data
    //
    int n = 6;

    //
    // Decision variables
    //
    IntVar[] x = solver.MakeIntVarArray(n, 0, n - 1 , "x");

    //
    // Constraints
    //
    AllDifferentExcept0(solver, x);

    // we also require at least 2 0's
    IntVar[] z_tmp = new IntVar[n];
    for(int i = 0; i < n; i++) {
      z_tmp[i] = x[i] == 0;
    }
    IntVar z = z_tmp.Sum().VarWithName("z");
    solver.Add(z == 2);


    //
    // Search
    //
    DecisionBuilder db = solver.MakePhase(x,
                                          Solver.CHOOSE_FIRST_UNBOUND,
                                          Solver.INT_VALUE_DEFAULT);

    solver.NewSearch(db);
    while (solver.NextSolution()) {
      Console.Write("z: {0}  x: ", z.Value());
      for(int i = 0; i < n; i++) {
        Console.Write("{0} ", x[i].Value());
      }

      Console.WriteLine();
    }

    Console.WriteLine("\nSolutions: {0}", solver.Solutions());
    Console.WriteLine("WallTime: {0}ms", solver.WallTime());
    Console.WriteLine("Failures: {0}", solver.Failures());
    Console.WriteLine("Branches: {0} ", solver.Branches());

    solver.EndSearch();

  }

  public static void Main(String[] args)
  {
    Solve();
  }
}