text: /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
  /*
   *  Main authors:
   *     Christian Schulte <schulte@gecode.org>
   *
   *  Copyright:
   *     Christian Schulte, 2001
   *
   *  Last modified:
   *     $Date: 2011-05-03 00:31:59 +1000 (Tue, 03 May 2011) $ by $Author: schulte $
   *     $Revision: 11982 $
   *
   *  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
   *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   */
  
  #include <gecode/driver.hh>
  #include <gecode/int.hh>
  #include <gecode/minimodel.hh>
  
  #if defined(GECODE_HAS_QT) && defined(GECODE_HAS_GIST)
  #include <QtGui>
  #endif
  
  using namespace Gecode;
  
  /**
   * \brief %Example: n-%Queens puzzle
   *
   * Place n queens on an n times n chessboard such that they do not
   * attack each other.
   *
   * \ingroup Example
   *
   */
  class Queens : public Script {
  public:
    /// Position of queens on boards
    IntVarArray q;
    /// Propagation to use for model
    enum {
      PROP_BINARY,  ///< Use only binary disequality constraints
      PROP_MIXED,   ///< Use single distinct and binary disequality constraints
      PROP_DISTINCT ///< Use three distinct constraints
    };
    /// The actual problem
    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++) {
            rel(*this, q[i] != q[j]);
            rel(*this, q[i]+i != q[j]+j);
            rel(*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++) {
            rel(*this, q[i]+i != q[j]+j);
            rel(*this, q[i]-i != q[j]-j);
          }
        distinct(*this, q, opt.icl());
        break;
      case PROP_DISTINCT:
        distinct(*this, IntArgs::create(n,0,1), q, opt.icl());
        distinct(*this, IntArgs::create(n,0,-1), q, opt.icl());
        distinct(*this, q, opt.icl());
        break;
      }
      branch(*this, q, INT_VAR_SIZE_MIN, INT_VAL_MIN);
    }
  
    /// Constructor for cloning \a s
    Queens(bool share, Queens& s) : Script(share,s) {
      q.update(*this, share, s.q);
    }
  
    /// Perform copying during cloning
    virtual Space*
    copy(bool share) {
      return new Queens(share,*this);
    }
  
    /// Print solution
    virtual void
    print(std::ostream& os) const {
      os << "queens\t";
      for (int i = 0; i < q.size(); i++) {
        os << q[i] << ", ";
        if ((i+1) % 10 == 0)
          os << std::endl << "\t";
      }
      os << std::endl;
    }
  };
  
  #if defined(GECODE_HAS_QT) && defined(GECODE_HAS_GIST)
  /// Inspector showing queens on a chess board
  class QueensInspector : public Gist::Inspector {
  protected:
    /// The graphics scene displaying the board
    QGraphicsScene* scene;
    /// The window containing the graphics scene
    QMainWindow* mw;
    /// The size of a field on the board
    static const int unit = 20;
  public:
    /// Constructor
    QueensInspector(void) : scene(NULL), mw(NULL) {}
    /// Inspect space \a s
    virtual void inspect(const Space& s) {
      const Queens& q = static_cast<const Queens&>(s);
      
      if (!scene)
        initialize();
      QList <QGraphicsItem*> itemList = scene->items();
      foreach (QGraphicsItem* i, scene->items()) {
        scene->removeItem(i);
        delete i;
      }
  
      for (int i=0; i<q.q.size(); i++) {
        for (int j=0; j<q.q.size(); j++) {
          scene->addRect(i*unit,j*unit,unit,unit);
        }
        QBrush b(q.q[i].assigned() ? Qt::black : Qt::red);
        QPen p(q.q[i].assigned() ? Qt::black : Qt::white);
        for (IntVarValues xv(q.q[i]); xv(); ++xv) {
          scene->addEllipse(QRectF(i*unit+unit/4,xv.val()*unit+unit/4,
                                   unit/2,unit/2), p, b);
        } 
      }
      mw->show();    
    }
      
    /// Set up main window
    void initialize(void) {
      mw = new QMainWindow();
      scene = new QGraphicsScene();
      QGraphicsView* view = new QGraphicsView(scene);
      view->setRenderHints(QPainter::Antialiasing);
      mw->setCentralWidget(view);
      mw->setAttribute(Qt::WA_QuitOnClose, false);
      mw->setAttribute(Qt::WA_DeleteOnClose, false);
      QAction* closeWindow = new QAction("Close window", mw);
      closeWindow->setShortcut(QKeySequence("Ctrl+W"));
      mw->connect(closeWindow, SIGNAL(triggered()),
                  mw, SLOT(close()));
      mw->addAction(closeWindow);
    }
    
    /// Name of the inspector
    virtual std::string name(void) { return "Board"; }
    /// Finalize inspector
    virtual void finalize(void) {
      delete mw;
      mw = NULL;
    }
  };
  
  #endif /* GECODE_HAS_GIST */
  
  /** \brief Main-function
   *  \relates Queens
   */
  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");
  
  #if defined(GECODE_HAS_QT) && defined(GECODE_HAS_GIST)
    QueensInspector ki;
    opt.inspect.click(&ki);
  #endif
  
    opt.parse(argc,argv);
    Script::run<Queens,DFS,SizeOptions>(opt);
    return 0;
  }
  
  // STATISTICS: example-any
  
  