//
// 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
//
//
// 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 System.Collections;
using System.IO;
using System.Text.RegularExpressions;

public class Langford
{

/**
*
* Langford number problem.
* See http://www.hakank.org/or-tools/langford.py
*
*/
private static void Solve(int k = 8, int num_sol = 0)
{

Solver solver = new Solver("Langford");

Console.WriteLine("k: {0}", k);

//
// data
//
int p = 2*k;

//
// Decision variables
//
IntVar[] position = solver.MakeIntVarArray(p, 0, p-1, "position");
IntVar[] solution = solver.MakeIntVarArray(p, 1, k, "solution");

//
// Constraints
//

for(int i = 1; i <= k; i++) {
solver.Add(position[i+k-1] - (position[i-1] + solver.MakeIntVar(i+1,i+1)) == 0);
}

// Symmetry breaking

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

solver.NewSearch(db);

int num_solutions = 0;
while (solver.NextSolution()) {
Console.Write("solution : ");
for(int i = 0; i < p; i++) {
Console.Write(solution[i].Value() + " ");
}
Console.WriteLine();
num_solutions++;
if (num_sol > 0 && num_solutions >= num_sol) {
break;
}
}

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)
{
int k = 8;
int num_sol = 0; // 0: print all solutions

if (args.Length > 0) {
k = Convert.ToInt32(args[0]);
}

if (args.Length > 1) {
num_sol = Convert.ToInt32(args[1]);
}

Solve(k, num_sol);

}
}