lemon/concepts/heap.h
changeset 180 4b9ab1324c3b
parent 100 4f754b4cf82b
child 203 215bfc30b14f
equal deleted inserted replaced
0:79b525502e1c 1:2b12834fd68c
    16  *
    16  *
    17  */
    17  */
    18 
    18 
    19 ///\ingroup concept
    19 ///\ingroup concept
    20 ///\file
    20 ///\file
    21 ///\brief Classes for representing heaps.
    21 ///\brief The concept of heaps.
    22 ///
       
    23 
    22 
    24 #ifndef LEMON_CONCEPT_HEAP_H
    23 #ifndef LEMON_CONCEPT_HEAP_H
    25 #define LEMON_CONCEPT_HEAP_H
    24 #define LEMON_CONCEPT_HEAP_H
    26 
    25 
    27 #include <lemon/bits/invalid.h>
    26 #include <lemon/bits/invalid.h>
    28 
    27 
    29 namespace lemon {
    28 namespace lemon {
       
    29 
    30   namespace concepts {
    30   namespace concepts {
       
    31 
    31     /// \addtogroup concept
    32     /// \addtogroup concept
    32     /// @{
    33     /// @{
    33 
    34 
    34 
    35     /// \brief The heap concept.
    35     /// \brief A concept structure describes the main interface of heaps.
       
    36     ///
    36     ///
    37     /// A concept structure describes the main interface of heaps.
    37     /// Concept class describing the main interface of heaps.
    38     ///
    38     template <typename Priority, typename ItemIntMap>
    39     template <typename Prio, typename ItemIntMap>
       
    40     class Heap {
    39     class Heap {
    41     public:
    40     public:
    42 
    41 
    43       ///\brief Type of the items stored in the heap.
    42       /// Type of the items stored in the heap.
    44       typedef typename ItemIntMap::Key  Item;
    43       typedef typename ItemIntMap::Key Item;
    45   
    44 
    46 
    45       /// Type of the priorities.
    47       /// \brief Type to represent the items states.
    46       typedef Priority Prio;
    48       ///
    47 
    49       /// Each Item element have a state associated to it. It may be "in heap",
    48       /// \brief Type to represent the states of the items.
    50       /// "pre heap" or "post heap". The later two are indifferent from the
    49       ///
    51       /// heap's point of view, but may be useful to the user.
    50       /// Each item has a state associated to it. It can be "in heap",
    52       ///
    51       /// "pre heap" or "post heap". The later two are indifferent
    53       /// The ItemIntMap _should_ be initialized in such way, that it maps
    52       /// from the point of view of the heap, but may be useful for
    54       /// PRE_HEAP (-1) to any element to be put in the heap...
    53       /// the user.
       
    54       ///
       
    55       /// The \c ItemIntMap must be initialized in such a way, that it 
       
    56       /// assigns \c PRE_HEAP (<tt>-1</tt>) to every item.
    55       enum State {
    57       enum State {
    56 	IN_HEAP = 0,
    58 	IN_HEAP = 0,
    57 	PRE_HEAP = -1,
    59 	PRE_HEAP = -1,
    58 	POST_HEAP = -2
    60 	POST_HEAP = -2
    59       };
    61       };
    60       
    62       
    61       /// \brief The constructor.
    63       /// \brief The constructor.
    62       ///
    64       ///
    63       /// The constructor.
    65       /// The constructor.
    64       /// \param _iim should be given to the constructor, since it is used
    66       /// \param map A map that assigns \c int values to keys of type
    65       /// internally to handle the cross references. The value of the map
    67       /// \c Item. It is used internally by the heap implementations to
    66       /// should be PRE_HEAP (-1) for each element.
    68       /// handle the cross references. The assigned value must be
    67       explicit Heap(ItemIntMap &_iim) {}
    69       /// \c PRE_HEAP (<tt>-1</tt>) for every item.
       
    70       explicit Heap(ItemIntMap &map) {}
    68 
    71 
    69       /// \brief The number of items stored in the heap.
    72       /// \brief The number of items stored in the heap.
    70       ///
    73       ///
    71       /// Returns the number of items stored in the heap.
    74       /// Returns the number of items stored in the heap.
    72       int size() const { return 0; }
    75       int size() const { return 0; }
    73 
    76 
    74       /// \brief Checks if the heap stores no items.
    77       /// \brief Checks if the heap is empty.
    75       ///
    78       ///
    76       /// Returns \c true if and only if the heap stores no items.
    79       /// Returns \c true if the heap is empty.
    77       bool empty() const { return false; }
    80       bool empty() const { return false; }
    78 
    81 
    79       /// \brief Makes empty this heap.
    82       /// \brief Makes the heap empty.
    80       ///
    83       ///
    81       /// Makes this heap empty.
    84       /// Makes the heap empty.
    82       void clear();
    85       void clear();
    83 
    86 
    84       /// \brief Insert an item into the heap with the given heap.
    87       /// \brief Inserts an item into the heap with the given priority.
    85       ///    
    88       ///    
    86       /// Adds \c i to the heap with priority \c p. 
    89       /// Inserts the given item into the heap with the given priority. 
    87       /// \param i The item to insert.
    90       /// \param i The item to insert.
    88       /// \param p The priority of the item.
    91       /// \param p The priority of the item.
    89       void push(const Item &i, const Prio &p) {}
    92       void push(const Item &i, const Prio &p) {}
    90 
    93 
    91       /// \brief Returns the item with minimum priority.
    94       /// \brief Returns the item having minimum priority.
    92       ///
    95       ///
    93       /// This method returns the item with minimum priority.  
    96       /// Returns the item having minimum priority.
    94       /// \pre The heap must be nonempty.  
    97       /// \pre The heap must be non-empty.
    95       Item top() const {}
    98       Item top() const {}
    96 
    99 
    97       /// \brief Returns the minimum priority.
   100       /// \brief The minimum priority.
    98       ///
   101       ///
    99       /// It returns the minimum priority.
   102       /// Returns the minimum priority.
   100       /// \pre The heap must be nonempty.
   103       /// \pre The heap must be non-empty.
   101       Prio prio() const {}
   104       Prio prio() const {}
   102 
   105 
   103       /// \brief Deletes the item with minimum priority.
   106       /// \brief Removes the item having minimum priority.
   104       ///
   107       ///
   105       /// This method deletes the item with minimum priority.
   108       /// Removes the item having minimum priority.
   106       /// \pre The heap must be non-empty.  
   109       /// \pre The heap must be non-empty.
   107       void pop() {}
   110       void pop() {}
   108 
   111 
   109       /// \brief Deletes \c i from the heap.
   112       /// \brief Removes an item from the heap.
   110       ///
   113       ///
   111       /// This method deletes item \c i from the heap, if \c i was
   114       /// Removes the given item from the heap if it is already stored.
       
   115       /// \param i The item to delete. 
       
   116       void erase(const Item &i) {}
       
   117 
       
   118       /// \brief The priority of an item.
       
   119       ///
       
   120       /// Returns the priority of the given item.  
       
   121       /// \pre \c i must be in the heap.
       
   122       /// \param i The item.
       
   123       Prio operator[](const Item &i) const {}
       
   124 
       
   125       /// \brief Sets the priority of an item or inserts it, if it is
       
   126       /// not stored in the heap.
       
   127       ///
       
   128       /// This method sets the priority of the given item if it is
   112       /// already stored in the heap.
   129       /// already stored in the heap.
   113       /// \param i The item to erase. 
   130       /// Otherwise it inserts the given item with the given priority.
   114       void erase(const Item &i) {}
   131       ///
   115 
   132       /// It may throw an \ref UnderflowPriorityException.
   116       /// \brief Returns the priority of \c i.
       
   117       ///
       
   118       /// This function returns the priority of item \c i.  
       
   119       /// \pre \c i must be in the heap.
       
   120       /// \param i The item.
       
   121       Prio operator[](const Item &i) const {}
       
   122 
       
   123       /// \brief \c i gets to the heap with priority \c p independently 
       
   124       /// if \c i was already there.
       
   125       ///
       
   126       /// This method calls \ref push(\c i, \c p) if \c i is not stored
       
   127       /// in the heap and sets the priority of \c i to \c p otherwise.
       
   128       /// It may throw an \e UnderFlowPriorityException. 
       
   129       /// \param i The item.
   133       /// \param i The item.
   130       /// \param p The priority.
   134       /// \param p The priority.
   131       void set(const Item &i, const Prio &p) {}
   135       void set(const Item &i, const Prio &p) {}
   132       
   136       
   133       /// \brief Decreases the priority of \c i to \c p.
   137       /// \brief Decreases the priority of an item to the given value.
   134       ///
   138       ///
   135       /// This method decreases the priority of item \c i to \c p.
   139       /// Decreases the priority of an item to the given value.
   136       /// \pre \c i must be stored in the heap with priority at least \c p.
   140       /// \pre \c i must be stored in the heap with priority at least \c p.
   137       /// \param i The item.
   141       /// \param i The item.
   138       /// \param p The priority.
   142       /// \param p The priority.
   139       void decrease(const Item &i, const Prio &p) {}
   143       void decrease(const Item &i, const Prio &p) {}
   140 
   144 
   141       /// \brief Increases the priority of \c i to \c p.
   145       /// \brief Increases the priority of an item to the given value.
   142       ///
   146       ///
   143       /// This method sets the priority of item \c i to \c p. 
   147       /// Increases the priority of an item to the given value.
   144       /// \pre \c i must be stored in the heap with priority at most \c
   148       /// \pre \c i must be stored in the heap with priority at most \c p.
   145       /// p relative to \c Compare.
       
   146       /// \param i The item.
   149       /// \param i The item.
   147       /// \param p The priority.
   150       /// \param p The priority.
   148       void increase(const Item &i, const Prio &p) {}
   151       void increase(const Item &i, const Prio &p) {}
   149 
   152 
   150       /// \brief Returns if \c item is in, has already been in, or has 
   153       /// \brief Returns if an item is in, has already been in, or has
   151       /// never been in the heap.
   154       /// never been in the heap.
   152       ///
   155       ///
   153       /// This method returns PRE_HEAP if \c item has never been in the
   156       /// This method returns \c PRE_HEAP if the given item has never
   154       /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
   157       /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
   155       /// otherwise. In the latter case it is possible that \c item will
   158       /// and \c POST_HEAP otherwise.
   156       /// get back to the heap again.
   159       /// In the latter case it is possible that the item will get back
       
   160       /// to the heap again.
   157       /// \param i The item.
   161       /// \param i The item.
   158       State state(const Item &i) const {}
   162       State state(const Item &i) const {}
   159 
   163 
   160       /// \brief Sets the state of the \c item in the heap.
   164       /// \brief Sets the state of an item in the heap.
   161       ///
   165       ///
   162       /// Sets the state of the \c item in the heap. It can be used to
   166       /// Sets the state of the given item in the heap. It can be used
   163       /// manually clear the heap when it is important to achive the
   167       /// to manually clear the heap when it is important to achive the
   164       /// better time complexity.
   168       /// better time complexity.
   165       /// \param i The item.
   169       /// \param i The item.
   166       /// \param st The state. It should not be \c IN_HEAP. 
   170       /// \param st The state. It should not be \c IN_HEAP.
   167       void state(const Item& i, State st) {}
   171       void state(const Item& i, State st) {}
   168 
   172 
   169 
   173 
   170       template <typename _Heap>
   174       template <typename _Heap>
   171       struct Constraints {
   175       struct Constraints {
   172       public:
   176       public:
   173     
       
   174 	void constraints() {
   177 	void constraints() {
       
   178 	  typedef typename _Heap::Item OwnItem;
       
   179 	  typedef typename _Heap::Prio OwnPrio;
       
   180 	  typedef typename _Heap::State OwnState;
       
   181 
   175 	  Item item;
   182 	  Item item;
   176 	  Prio prio;
   183 	  Prio prio;
   177 
   184 	  State state;
   178 	  item=Item();
   185 	  item=Item();
   179 	  prio=Prio();
   186 	  prio=Prio();
   180 
       
   181 	  ignore_unused_variable_warning(item);
   187 	  ignore_unused_variable_warning(item);
   182 	  ignore_unused_variable_warning(prio);
   188 	  ignore_unused_variable_warning(prio);
   183 
       
   184 	  typedef typename _Heap::State State;
       
   185 	  State state;
       
   186 
       
   187 	  ignore_unused_variable_warning(state);
   189 	  ignore_unused_variable_warning(state);
   188       
   190 
   189 	  _Heap heap1 = _Heap(map);
   191 	  OwnItem own_item;
   190 
   192 	  OwnPrio own_prio;
       
   193 	  OwnState own_state;
       
   194 	  own_item=Item();
       
   195 	  own_prio=Prio();
       
   196 	  ignore_unused_variable_warning(own_item);
       
   197 	  ignore_unused_variable_warning(own_prio);
       
   198 	  ignore_unused_variable_warning(own_state);
       
   199 
       
   200 	  _Heap heap1(map);
       
   201 	  _Heap heap2 = heap1;
   191 	  ignore_unused_variable_warning(heap1);
   202 	  ignore_unused_variable_warning(heap1);
   192       
   203 	  ignore_unused_variable_warning(heap2);
   193 	  heap.push(item, prio);
   204 	  
       
   205 	  int s = heap.size();
       
   206 	  bool e = heap.empty();
   194 
   207 
   195 	  prio = heap.prio();
   208 	  prio = heap.prio();
   196 	  item = heap.top();
   209 	  item = heap.top();
   197 
   210 	  prio = heap[item];
       
   211 	  own_prio = heap.prio();
       
   212 	  own_item = heap.top();
       
   213 	  own_prio = heap[own_item];
       
   214 
       
   215 	  heap.push(item, prio);
       
   216 	  heap.push(own_item, own_prio);
   198 	  heap.pop();
   217 	  heap.pop();
   199 
   218 
   200 	  heap.set(item, prio);
   219 	  heap.set(item, prio);
   201 	  heap.decrease(item, prio);
   220 	  heap.decrease(item, prio);
   202 	  heap.increase(item, prio);
   221 	  heap.increase(item, prio);
   203 	  prio = heap[item];
   222 	  heap.set(own_item, own_prio);
       
   223 	  heap.decrease(own_item, own_prio);
       
   224 	  heap.increase(own_item, own_prio);
   204 
   225 
   205 	  heap.erase(item);
   226 	  heap.erase(item);
       
   227 	  heap.erase(own_item);
       
   228 	  heap.clear();
   206 
   229 
   207 	  state = heap.state(item);
   230 	  state = heap.state(item);
       
   231 	  heap.state(item, state);
       
   232 	  state = heap.state(own_item);
       
   233 	  heap.state(own_item, own_state);
   208 
   234 
   209 	  state = _Heap::PRE_HEAP;
   235 	  state = _Heap::PRE_HEAP;
   210 	  state = _Heap::IN_HEAP;
   236 	  state = _Heap::IN_HEAP;
   211 	  state = _Heap::POST_HEAP;
   237 	  state = _Heap::POST_HEAP;
   212 
   238 	  own_state = _Heap::PRE_HEAP;
   213 	  heap.clear();
   239 	  own_state = _Heap::IN_HEAP;
       
   240 	  own_state = _Heap::POST_HEAP;
   214 	}
   241 	}
   215     
   242 
   216 	_Heap& heap;
   243 	_Heap& heap;
   217 	ItemIntMap& map;
   244 	ItemIntMap& map;
   218 
       
   219 	Constraints() : heap(0), map(0) {}
       
   220       };
   245       };
   221     };
   246     };
   222 
   247 
   223     /// @}
   248     /// @}
   224   } // namespace lemon
   249   } // namespace lemon