schurs-lemma.cpp

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2011
 *
 *  Last modified:
 *     $Date: 2011-07-08 12:09:31 +0200 (Fri, 08 Jul 2011) $ by $Author: schulte $
 *     $Revision: 12164 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining
 *  a copy of this software and associated documentation files (the
 *  "Software"), to deal in the Software without restriction, including
 *  without limitation the rights to use, copy, modify, merge, publish,
 *  distribute, sublicense, and/or sell copies of the Software, and to
 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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 */

#include <gecode/driver.hh>
#include <gecode/int.hh>
#include <gecode/minimodel.hh>

using namespace Gecode;

class SchurOptions : public Options {
public:
  int c, n; 

  SchurOptions(const char* s, int c0, int n0)
    : Options(s), c(c0), n(n0) {}
  void parse(int& argc, char* argv[]) {
    Options::parse(argc,argv);
    if (argc < 3)
      return;
    c = atoi(argv[1]);
    n = atoi(argv[2]);
  }
  virtual void help(void) {
    Options::help();
    std::cerr << "\t(unsigned int) default: " << c << std::endl
              << "\t\tparameter c (number of boxes)" << std::endl
              << "\t(unsigned int) default: " << n << std::endl
              << "\t\tparameter n (number of balls)" << std::endl;
  }
};


class Schur : public Script {
protected:
  IntVarArray box;
public:
  Schur(const SchurOptions& opt) : box(*this,opt.n,1,opt.c) {
    int n = opt.n;

    IntVarArgs triple(3);

    // Iterate over balls and find triples
    for (int i=1; i<=n; i++) {
      triple[0] = box[i-1];
      for (int j=1; i+j<=n; j++) {
        triple[1] = box[j-1];
        triple[2] = box[i+j-1];
        rel(*this, triple, IRT_NQ);
      }
    }

    // Break value symmetries
    precede(*this, box, IntArgs::create(opt.c, 1));

    branch(*this, box, INT_VAR_SIZE_AFC_MIN, INT_VAL_MIN);
  }
  virtual void
  print(std::ostream& os) const {
    os << "\t" << box << std::endl;
  }

  Schur(bool share, Schur& s) : Script(share,s) {
    box.update(*this, share, s.box);
  }
  virtual Space*
  copy(bool share) {
    return new Schur(share,*this);
  }
};

int
main(int argc, char* argv[]) {
  SchurOptions opt("Schur's Lemma",3,13);
  opt.parse(argc,argv);
  Script::run<Schur,DFS,SchurOptions>(opt);
  return 0;
}

// STATISTICS: example-any