/* -*- mode: C++; indent-tabs-mode: nil; -*-
* This file is a part of LEMON, a generic C++ optimization library.
* Copyright (C) 2003-2009
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
* (Egervary Research Group on Combinatorial Optimization, EGRES).
* Permission to use, modify and distribute this software is granted
* provided that this copyright notice appears in all copies. For
* precise terms see the accompanying LICENSE file.
* This software is provided "AS IS" with no warranty of any kind,
* express or implied, and with no claim as to its suitability for any
#ifndef LEMON_CONCEPTS_HEAP_H
#define LEMON_CONCEPTS_HEAP_H
///\brief The concept of heaps.
#include <lemon/concept_check.h>
/// \brief The heap concept.
/// This concept class describes the main interface of heaps.
/// The various \ref heaps "heap structures" are efficient
/// implementations of the abstract data type \e priority \e queue.
/// They store items with specified values called \e priorities
/// in such a way that finding and removing the item with minimum
/// priority are efficient. The basic operations are adding and
/// erasing items, changing the priority of an item, etc.
/// Heaps are crucial in several algorithms, such as Dijkstra and Prim.
/// Any class that conforms to this concept can be used easily in such
/// \tparam PR Type of the priorities of the items.
/// \tparam IM A read-writable item map with \c int values, used
/// internally to handle the cross references.
/// \tparam CMP A functor class for comparing the priorities.
/// The default is \c std::less<PR>.
template <typename PR, typename IM, typename CMP>
template <typename PR, typename IM, typename CMP = std::less<PR> >
/// Type of the item-int map.
/// Type of the priorities.
/// Type of the items stored in the heap.
typedef typename ItemIntMap::Key Item;
/// \brief Type to represent the states of the items.
/// Each item has a state associated to it. It can be "in heap",
/// "pre-heap" or "post-heap". The latter two are indifferent from the
/// heap's point of view, but may be useful to the user.
/// The item-int map must be initialized in such way that it assigns
/// \c PRE_HEAP (<tt>-1</tt>) to any element to be put in the heap.
IN_HEAP = 0, ///< = 0. The "in heap" state constant.
PRE_HEAP = -1, ///< = -1. The "pre-heap" state constant.
POST_HEAP = -2 ///< = -2. The "post-heap" state constant.
/// \param map A map that assigns \c int values to keys of type
/// \c Item. It is used internally by the heap implementations to
/// handle the cross references. The assigned value must be
/// \c PRE_HEAP (<tt>-1</tt>) for each item.
explicit Heap(ItemIntMap &map) {}
explicit Heap(ItemIntMap&) {}
/// \param map A map that assigns \c int values to keys of type
/// \c Item. It is used internally by the heap implementations to
/// handle the cross references. The assigned value must be
/// \c PRE_HEAP (<tt>-1</tt>) for each item.
/// \param comp The function object used for comparing the priorities.
explicit Heap(ItemIntMap &map, const CMP &comp) {}
explicit Heap(ItemIntMap&, const CMP&) {}
/// \brief The number of items stored in the heap.
/// This function returns the number of items stored in the heap.
int size() const { return 0; }
/// \brief Check if the heap is empty.
/// This function returns \c true if the heap is empty.
bool empty() const { return false; }
/// \brief Make the heap empty.
/// This functon makes the heap empty.
/// It does not change the cross reference map. If you want to reuse
/// a heap that is not surely empty, you should first clear it and
/// then you should set the cross reference map to \c PRE_HEAP
/// \brief Insert an item into the heap with the given priority.
/// This function inserts the given item into the heap with the
/// \param i The item to insert.
/// \param p The priority of the item.
/// \pre \e i must not be stored in the heap.
void push(const Item &i, const Prio &p) {}
void push(const Item&, const Prio&) {}
/// \brief Return the item having minimum priority.
/// This function returns the item having minimum priority.
/// \pre The heap must be non-empty.
Item top() const { return Item(); }
/// \brief The minimum priority.
/// This function returns the minimum priority.
/// \pre The heap must be non-empty.
Prio prio() const { return Prio(); }
/// \brief Remove the item having minimum priority.
/// This function removes the item having minimum priority.
/// \pre The heap must be non-empty.
/// \brief Remove the given item from the heap.
/// This function removes the given item from the heap if it is
/// \param i The item to delete.
/// \pre \e i must be in the heap.
void erase(const Item &i) {}
void erase(const Item&) {}
/// \brief The priority of the given item.
/// This function returns the priority of the given item.
/// \pre \e i must be in the heap.
Prio operator[](const Item &i) const {}
Prio operator[](const Item&) const { return Prio(); }
/// \brief Set the priority of an item or insert it, if it is
/// not stored in the heap.
/// This method sets the priority of the given item if it is
/// already stored in the heap. Otherwise it inserts the given
/// item into the heap with the given priority.
/// \param p The priority.
void set(const Item &i, const Prio &p) {}
void set(const Item&, const Prio&) {}
/// \brief Decrease the priority of an item to the given value.
/// This function decreases the priority of an item to the given value.
/// \param p The priority.
/// \pre \e i must be stored in the heap with priority at least \e p.
void decrease(const Item &i, const Prio &p) {}
void decrease(const Item&, const Prio&) {}
/// \brief Increase the priority of an item to the given value.
/// This function increases the priority of an item to the given value.
/// \param p The priority.
/// \pre \e i must be stored in the heap with priority at most \e p.
void increase(const Item &i, const Prio &p) {}
void increase(const Item&, const Prio&) {}
/// \brief Return the state of an item.
/// This method returns \c PRE_HEAP if the given item has never
/// been in the heap, \c IN_HEAP if it is in the heap at the moment,
/// and \c POST_HEAP otherwise.
/// In the latter case it is possible that the item will get back
State state(const Item &i) const {}
State state(const Item&) const { return PRE_HEAP; }
/// \brief Set the state of an item in the heap.
/// This function sets the state of the given item in the heap.
/// It can be used to manually clear the heap when it is important
/// to achive better time complexity.
/// \param st The state. It should not be \c IN_HEAP.
void state(const Item& i, State st) {}
void state(const Item&, State) {}
template <typename _Heap>
typedef typename _Heap::Item OwnItem;
typedef typename _Heap::Prio OwnPrio;
typedef typename _Heap::State OwnState;
ignore_unused_variable_warning(item);
ignore_unused_variable_warning(prio);
ignore_unused_variable_warning(own_item);
ignore_unused_variable_warning(own_prio);
ignore_unused_variable_warning(own_state);
ignore_unused_variable_warning(heap1);
ignore_unused_variable_warning(heap2);
ignore_unused_variable_warning(s);
ignore_unused_variable_warning(e);
own_prio = heap[own_item];
heap.push(own_item, own_prio);
heap.decrease(item, prio);
heap.increase(item, prio);
heap.set(own_item, own_prio);
heap.decrease(own_item, own_prio);
heap.increase(own_item, own_prio);
own_state = heap.state(own_item);
heap.state(own_item, own_state);
own_state = _Heap::PRE_HEAP;
own_state = _Heap::IN_HEAP;
own_state = _Heap::POST_HEAP;
