lemon/dheap.h
changeset 873 23da1b807280
parent 706 9314d9339475
equal deleted inserted replaced
3:1904302e42ef 0:30575ee5f5a5
    14  * express or implied, and with no claim as to its suitability for any
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    15  * purpose.
    16  *
    16  *
    17  */
    17  */
    18 
    18 
    19 #ifndef LEMON_KARY_HEAP_H
    19 #ifndef LEMON_DHEAP_H
    20 #define LEMON_KARY_HEAP_H
    20 #define LEMON_DHEAP_H
    21 
    21 
    22 ///\ingroup heaps
    22 ///\ingroup heaps
    23 ///\file
    23 ///\file
    24 ///\brief Fourary heap implementation.
    24 ///\brief D-ary heap implementation.
    25 
    25 
    26 #include <vector>
    26 #include <vector>
    27 #include <utility>
    27 #include <utility>
    28 #include <functional>
    28 #include <functional>
    29 
    29 
    30 namespace lemon {
    30 namespace lemon {
    31 
    31 
    32   /// \ingroup heaps
    32   /// \ingroup heaps
    33   ///
    33   ///
    34   ///\brief K-ary heap data structure.
    34   ///\brief D-ary heap data structure.
    35   ///
    35   ///
    36   /// This class implements the \e K-ary \e heap data structure.
    36   /// This class implements the \e D-ary \e heap data structure.
    37   /// It fully conforms to the \ref concepts::Heap "heap concept".
    37   /// It fully conforms to the \ref concepts::Heap "heap concept".
    38   ///
    38   ///
    39   /// The \ref KaryHeap "K-ary heap" is a generalization of the
    39   /// The \ref DHeap "D-ary heap" is a generalization of the
    40   /// \ref BinHeap "binary heap" structure, its nodes have at most
    40   /// \ref BinHeap "binary heap" structure, its nodes have at most
    41   /// \c K children, instead of two.
    41   /// \c D children, instead of two.
    42   /// \ref BinHeap and \ref FouraryHeap are specialized implementations
    42   /// \ref BinHeap and \ref QuadHeap are specialized implementations
    43   /// of this structure for <tt>K=2</tt> and <tt>K=4</tt>, respectively.
    43   /// of this structure for <tt>D=2</tt> and <tt>D=4</tt>, respectively.
    44   ///
    44   ///
    45   /// \tparam PR Type of the priorities of the items.
    45   /// \tparam PR Type of the priorities of the items.
    46   /// \tparam IM A read-writable item map with \c int values, used
    46   /// \tparam IM A read-writable item map with \c int values, used
    47   /// internally to handle the cross references.
    47   /// internally to handle the cross references.
    48   /// \tparam K The degree of the heap, each node have at most \e K
    48   /// \tparam D The degree of the heap, each node have at most \e D
    49   /// children. The default is 16. Powers of two are suggested to use
    49   /// children. The default is 16. Powers of two are suggested to use
    50   /// so that the multiplications and divisions needed to traverse the
    50   /// so that the multiplications and divisions needed to traverse the
    51   /// nodes of the heap could be performed faster.
    51   /// nodes of the heap could be performed faster.
    52   /// \tparam CMP A functor class for comparing the priorities.
    52   /// \tparam CMP A functor class for comparing the priorities.
    53   /// The default is \c std::less<PR>.
    53   /// The default is \c std::less<PR>.
    54   ///
    54   ///
    55   ///\sa BinHeap
    55   ///\sa BinHeap
    56   ///\sa FouraryHeap
    56   ///\sa FouraryHeap
    57 #ifdef DOXYGEN
    57 #ifdef DOXYGEN
    58   template <typename PR, typename IM, int K, typename CMP>
    58   template <typename PR, typename IM, int D, typename CMP>
    59 #else
    59 #else
    60   template <typename PR, typename IM, int K = 16,
    60   template <typename PR, typename IM, int D = 16,
    61             typename CMP = std::less<PR> >
    61             typename CMP = std::less<PR> >
    62 #endif
    62 #endif
    63   class KaryHeap {
    63   class DHeap {
    64   public:
    64   public:
    65     /// Type of the item-int map.
    65     /// Type of the item-int map.
    66     typedef IM ItemIntMap;
    66     typedef IM ItemIntMap;
    67     /// Type of the priorities.
    67     /// Type of the priorities.
    68     typedef PR Prio;
    68     typedef PR Prio;
    97     ///
    97     ///
    98     /// Constructor.
    98     /// Constructor.
    99     /// \param map A map that assigns \c int values to the items.
    99     /// \param map A map that assigns \c int values to the items.
   100     /// It is used internally to handle the cross references.
   100     /// It is used internally to handle the cross references.
   101     /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
   101     /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
   102     explicit KaryHeap(ItemIntMap &map) : _iim(map) {}
   102     explicit DHeap(ItemIntMap &map) : _iim(map) {}
   103 
   103 
   104     /// \brief Constructor.
   104     /// \brief Constructor.
   105     ///
   105     ///
   106     /// Constructor.
   106     /// Constructor.
   107     /// \param map A map that assigns \c int values to the items.
   107     /// \param map A map that assigns \c int values to the items.
   108     /// It is used internally to handle the cross references.
   108     /// It is used internally to handle the cross references.
   109     /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
   109     /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
   110     /// \param comp The function object used for comparing the priorities.
   110     /// \param comp The function object used for comparing the priorities.
   111     KaryHeap(ItemIntMap &map, const Compare &comp)
   111     DHeap(ItemIntMap &map, const Compare &comp)
   112       : _iim(map), _comp(comp) {}
   112       : _iim(map), _comp(comp) {}
   113 
   113 
   114     /// \brief The number of items stored in the heap.
   114     /// \brief The number of items stored in the heap.
   115     ///
   115     ///
   116     /// This function returns the number of items stored in the heap.
   116     /// This function returns the number of items stored in the heap.
   129     /// then you should set the cross reference map to \c PRE_HEAP
   129     /// then you should set the cross reference map to \c PRE_HEAP
   130     /// for each item.
   130     /// for each item.
   131     void clear() { _data.clear(); }
   131     void clear() { _data.clear(); }
   132 
   132 
   133   private:
   133   private:
   134     int parent(int i) { return (i-1)/K; }
   134     int parent(int i) { return (i-1)/D; }
   135     int firstChild(int i) { return K*i+1; }
   135     int firstChild(int i) { return D*i+1; }
   136 
   136 
   137     bool less(const Pair &p1, const Pair &p2) const {
   137     bool less(const Pair &p1, const Pair &p2) const {
   138       return _comp(p1.second, p2.second);
   138       return _comp(p1.second, p2.second);
   139     }
   139     }
   140 
   140 
   149     }
   149     }
   150 
   150 
   151     void bubbleDown(int hole, Pair p, int length) {
   151     void bubbleDown(int hole, Pair p, int length) {
   152       if( length>1 ) {
   152       if( length>1 ) {
   153         int child = firstChild(hole);
   153         int child = firstChild(hole);
   154         while( child+K<=length ) {
   154         while( child+D<=length ) {
   155           int min=child;
   155           int min=child;
   156           for (int i=1; i<K; ++i) {
   156           for (int i=1; i<D; ++i) {
   157             if( less(_data[child+i], _data[min]) )
   157             if( less(_data[child+i], _data[min]) )
   158               min=child+i;
   158               min=child+i;
   159           }
   159           }
   160           if( !less(_data[min], p) )
   160           if( !less(_data[min], p) )
   161             goto ok;
   161             goto ok;
   343       _iim.set(i, _iim[j]);
   343       _iim.set(i, _iim[j]);
   344       _iim.set(j, idx);
   344       _iim.set(j, idx);
   345       _data[idx].first=j;
   345       _data[idx].first=j;
   346     }
   346     }
   347 
   347 
   348   }; // class KaryHeap
   348   }; // class DHeap
   349 
   349 
   350 } // namespace lemon
   350 } // namespace lemon
   351 
   351 
   352 #endif // LEMON_KARY_HEAP_H
   352 #endif // LEMON_DHEAP_H