queens.cc

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2001
 *
 *  Last modified:
 *     $Date: 2008-01-08 16:09:27 +0100 (Tue, 08 Jan 2008) $ by $Author: nikopp $
 *     $Revision: 5789 $
 *
 *  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
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 *  permit persons to whom the Software is furnished to do so, subject to
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#include "examples/support.hh"
#include "gecode/minimodel.hh"

class Queens : public Example {
protected:
  IntVarArray q;
public:
  enum {
    PROP_BINARY,  
    PROP_MIXED,   
    PROP_DISTINCT 
  };
  Queens(const SizeOptions& opt)
    : q(this,opt.size(),0,opt.size()-1) {
    const int n = q.size();
    switch (opt.propagation()) {
    case PROP_BINARY:
      for (int i = 0; i<n; i++)
        for (int j = i+1; j<n; j++) {
          post(this, q[i] != q[j]);
          post(this, q[i]+i != q[j]+j);
          post(this, q[i]-i != q[j]-j);
        }
      break;
    case PROP_MIXED:
      for (int i = 0; i<n; i++)
        for (int j = i+1; j<n; j++) {
          post(this, q[i]+i != q[j]+j);
          post(this, q[i]-i != q[j]-j);
        }
      distinct(this, q, opt.icl());
      break;
    case PROP_DISTINCT:
      {
        IntArgs c(n);
        for (int i = n; i--; ) c[i] = i;
        distinct(this, c, q, opt.icl());
        for (int i = n; i--; ) c[i] = -i;
        distinct(this, c, q, opt.icl());
      }
      distinct(this, q, opt.icl());
      break;
    }
    branch(this, q, INT_VAR_SIZE_MIN, INT_VAL_MIN);
  }

  Queens(bool share, Queens& s) : Example(share,s) {
    q.update(this, share, s.q);
  }

  virtual Space*
  copy(bool share) {
    return new Queens(share,*this);
  }

  virtual void
  print(std::ostream& os) {
    os << "\t";
    for (int i = 0; i < q.size(); i++) {
      os << q[i] << ", ";
      if ((i+1) % 10 == 0)
        os << std::endl << "\t";
    }
    os << std::endl;
  }
  
  virtual void
  getVars(Gecode::Reflection::VarMap& vm, bool registerOnly) {
    vm.putArray(this,q,"q", registerOnly);
  }
};

int
main(int argc, char* argv[]) {
  SizeOptions opt("Queens");
  opt.iterations(500);
  opt.size(100);
  opt.propagation(Queens::PROP_DISTINCT);
  opt.propagation(Queens::PROP_BINARY, "binary",
                      "only binary disequality constraints");
  opt.propagation(Queens::PROP_MIXED, "mixed",
                      "single distinct and binary disequality constraints");
  opt.propagation(Queens::PROP_DISTINCT, "distinct",
                      "three distinct constraints");
  opt.parse(argc,argv);
  Example::run<Queens,DFS,SizeOptions>(opt);
  return 0;
}

// STATISTICS: example-any