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ranges-union.icc

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/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2004
 *
 *  Last modified:
 *     $Date: 2006-08-04 16:05:50 +0200 (Fri, 04 Aug 2006) $ by $Author: schulte $
 *     $Revision: 3515 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  See the file "LICENSE" for information on usage and
 *  redistribution of this file, and for a
 *     DISCLAIMER OF ALL WARRANTIES.
 *
 */

#include "gecode/support/static-pqueue.hh"

namespace Gecode { namespace Iter { namespace Ranges {

  template <class I, class J>
  class Union : public MinMax {
    I i;
    J j;
  public:


    Union(void);
    Union(I& i, J& j);
    void init(I& i, J& j);



    void operator++(void);
  };


  template <class I>
  class NaryUnion : public MinMax {
  protected:
    class RangeUnionOrder {
    public:
      bool operator()(const I&, const I&) const;
    };
    RangeUnionOrder order;
    Support::PQueue<I,RangeUnionOrder> r;
  public:


    NaryUnion(void);
    NaryUnion(I* i, int n);
    void init(I* i, int n);



    void operator++(void);
  };



  /*
   * Binary union
   *
   */

  template <class I, class J>
  inline void
  Union<I,J>::operator++(void) {
    if (!i() && !j()) {
      finish(); return;
    }
    if (!i()) {
      mi = j.min(); ma = j.max(); ++j; return;
    }
    if (!j()) {
      mi = i.min(); ma = i.max(); ++i; return;
    }
    if (i.min() < j.min()) {
      mi = i.min(); ma = i.max(); ++i;
    } else {
      mi = j.min(); ma = j.max(); ++j;
    }
    bool goOn;
    do {
      goOn = false;
      if (i() && (i.min() <= ma+1)) {
        ma = std::max(ma,i.max()); ++i; goOn=true;
      }
      if (j() && (j.min() <= ma+1)) {
        ma = std::max(ma,j.max()); ++j; goOn=true;
      }
    } while (goOn);
  }


  template <class I, class J>
  forceinline
  Union<I,J>::Union(void) {}

  template <class I, class J>
  forceinline
  Union<I,J>::Union(I& i0, J& j0)
    : i(i0), j(j0) {
    operator++();
  }

  template <class I, class J>
  forceinline void
  Union<I,J>::init(I& i0, J& j0) {
    i = i0; j = j0;
    operator++();
  }



  /*
   * Nary Union
   *
   */

  template <class I>
  forceinline bool
  NaryUnion<I>::RangeUnionOrder::operator()(const I& a, const I& b) const {
    return a.min() > b.min();
  }

  template <class I>
  inline void
  NaryUnion<I>::operator++(void) {
    if (r.empty()) {
      finish(); return;
    }
    mi = r.top().min();
    ma = r.top().max();
    do {
      if (ma < r.top().max())
        ma = r.top().max();
      ++(r.top());
      if (!(r.top())()) {
        r.remove();
        if (r.empty())
          return;
      } else {
        r.fix();
      }
    } while (ma+1 >= r.top().min());
  }


  template <class I>
  forceinline
  NaryUnion<I>::NaryUnion(void) {}

  template <class I>
  inline
  NaryUnion<I>::NaryUnion(I* r0, int n)
    : order(), r(n,order) {
    for (int i = n; i--; )
      if (r0[i]())
        r.insert(r0[i]);
    operator++();
  }

  template <class I>
  inline void
  NaryUnion<I>::init(I* r0, int n) {
    r.init(n,order);
    for (int i = n; i--; )
      if (r0[i]())
        r.insert(r0[i]);
    operator++();
  }

}}}

// STATISTICS: iter-any