to_num.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 ToNumTest
{


  /**
   *
   *  toNum(solver, a, num, base)
   *
   *  channelling between the array a and the number num.
   *
   */
  private static Constraint ToNum(IntVar[] a, IntVar num, int bbase) {
    int len = a.Length;

    IntVar[] tmp = new IntVar[len];
    for(int i = 0; i < len; i++) {
      tmp[i] = (a[i]*(int)Math.Pow(bbase,(len-i-1))).Var();
    }
     return tmp.Sum() == num;
  }



  /**
   *
   * Implements toNum: channeling between a number and an array.
   * See http://www.hakank.org/or-tools/toNum.py
   *
   */
  private static void Solve()
  {
    Solver solver = new Solver("ToNum");

    int n = 5;
    int bbase = 10;

    //
    // Decision variables
    //
    IntVar[] x = solver.MakeIntVarArray(n, 0, bbase - 1, "x");
    IntVar num = solver.MakeIntVar(0, (int)Math.Pow(bbase, n) - 1, "num");

    //
    // Constraints
    //

    solver.Add(x.AllDifferent());
    solver.Add(ToNum(x, num, bbase));

    // extra constraint (just for fun)
    // second digit should be 7
    // solver.Add(x[1] == 7);

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

    solver.NewSearch(db);

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

    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();
  }
}