diff --git a/lemon/binom_heap.h b/lemon/binom_heap.h --- a/lemon/binom_heap.h +++ b/lemon/binom_heap.h @@ -1,8 +1,8 @@ -/* -*- C++ -*- +/* -*- mode: C++; indent-tabs-mode: nil; -*- * - * This file is a part of LEMON, a generic C++ optimization library + * This file is a part of LEMON, a generic C++ optimization library. * - * Copyright (C) 2003-2008 + * Copyright (C) 2003-2009 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport * (Egervary Research Group on Combinatorial Optimization, EGRES). * @@ -20,193 +20,199 @@ #define LEMON_BINOM_HEAP_H ///\file -///\ingroup auxdat +///\ingroup heaps ///\brief Binomial Heap implementation. #include +#include #include #include #include namespace lemon { - /// \ingroup auxdat + /// \ingroup heaps /// - ///\brief Binomial Heap. + ///\brief Binomial heap data structure. /// - ///This class implements the \e Binomial \e heap data structure. A \e heap - ///is a data structure for storing items with specified values called \e - ///priorities in such a way that finding the item with minimum priority is - ///efficient. \c Compare specifies the ordering of the priorities. In a heap - ///one can change the priority of an item, add or erase an item, etc. + /// This class implements the \e binomial \e heap data structure. + /// It fully conforms to the \ref concepts::Heap "heap concept". /// - ///The methods \ref increase and \ref erase are not efficient in a Binomial - ///heap. In case of many calls to these operations, it is better to use a - ///\ref BinHeap "binary heap". + /// The methods \ref increase() and \ref erase() are not efficient + /// in a binomial heap. In case of many calls of these operations, + /// it is better to use other heap structure, e.g. \ref BinHeap + /// "binary heap". /// - ///\param _Prio Type of the priority of the items. - ///\param _ItemIntMap A read and writable Item int map, used internally - ///to handle the cross references. - ///\param _Compare A class for the ordering of the priorities. The - ///default is \c std::less<_Prio>. - /// - ///\sa BinHeap - ///\sa Dijkstra - ///\author Dorian Batha - + /// \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. #ifdef DOXYGEN - template + template #else - template > + template > #endif class BinomHeap { public: - typedef _ItemIntMap ItemIntMap; - typedef _Prio Prio; + /// Type of the item-int map. + typedef IM ItemIntMap; + /// Type of the priorities. + typedef PR Prio; + /// Type of the items stored in the heap. typedef typename ItemIntMap::Key Item; - typedef std::pair Pair; - typedef _Compare Compare; + /// Functor type for comparing the priorities. + typedef CMP Compare; + + /// \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 (-1) to any element to be put in the heap. + enum State { + IN_HEAP = 0, ///< = 0. + PRE_HEAP = -1, ///< = -1. + POST_HEAP = -2 ///< = -2. + }; private: class store; - std::vector container; - int minimum, head; - ItemIntMap &iimap; - Compare comp; - int num_items; + std::vector _data; + int _min, _head; + ItemIntMap &_iim; + Compare _comp; + int _num_items; public: - ///Status of the nodes - enum State { - ///The node is in the heap - IN_HEAP = 0, - ///The node has never been in the heap - PRE_HEAP = -1, - ///The node was in the heap but it got out of it - POST_HEAP = -2 - }; + /// \brief Constructor. + /// + /// Constructor. + /// \param map A map that assigns \c int values to the items. + /// It is used internally to handle the cross references. + /// The assigned value must be \c PRE_HEAP (-1) for each item. + explicit BinomHeap(ItemIntMap &map) + : _min(0), _head(-1), _iim(map), _num_items(0) {} - /// \brief The constructor + /// \brief Constructor. /// - /// \c _iimap should be given to the constructor, since it is - /// used internally to handle the cross references. - explicit BinomHeap(ItemIntMap &_iimap) - : minimum(0), head(-1), iimap(_iimap), num_items() {} - - /// \brief The constructor - /// - /// \c _iimap should be given to the constructor, since it is used - /// internally to handle the cross references. \c _comp is an - /// object for ordering of the priorities. - BinomHeap(ItemIntMap &_iimap, const Compare &_comp) - : minimum(0), head(-1), iimap(_iimap), comp(_comp), num_items() {} + /// Constructor. + /// \param map A map that assigns \c int values to the items. + /// It is used internally to handle the cross references. + /// The assigned value must be \c PRE_HEAP (-1) for each item. + /// \param comp The function object used for comparing the priorities. + BinomHeap(ItemIntMap &map, const Compare &comp) + : _min(0), _head(-1), _iim(map), _comp(comp), _num_items(0) {} /// \brief The number of items stored in the heap. /// - /// Returns the number of items stored in the heap. - int size() const { return num_items; } + /// This function returns the number of items stored in the heap. + int size() const { return _num_items; } - /// \brief Checks if the heap stores no items. + /// \brief Check if the heap is empty. /// - /// Returns \c true if and only if the heap stores no items. - bool empty() const { return num_items==0; } + /// This function returns \c true if the heap is empty. + bool empty() const { return _num_items==0; } - /// \brief Make empty this heap. + /// \brief Make the heap empty. /// - /// Make empty this heap. It does not change the cross reference - /// map. If you want to reuse a heap what is not surely empty you - /// should first clear the heap and after that you should set the - /// cross reference map for each item to \c PRE_HEAP. + /// 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 + /// for each item. void clear() { - container.clear(); minimum=0; num_items=0; head=-1; + _data.clear(); _min=0; _num_items=0; _head=-1; } - /// \brief \c item gets to the heap with priority \c value independently - /// if \c item was already there. + /// \brief Set the priority of an item or insert it, if it is + /// not stored in the heap. /// - /// This method calls \ref push(\c item, \c value) if \c item is not - /// stored in the heap and it calls \ref decrease(\c item, \c value) or - /// \ref increase(\c item, \c value) otherwise. + /// 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 item The item. + /// \param value The priority. void set (const Item& item, const Prio& value) { - int i=iimap[item]; - if ( i >= 0 && container[i].in ) { - if ( comp(value, container[i].prio) ) decrease(item, value); - if ( comp(container[i].prio, value) ) increase(item, value); + int i=_iim[item]; + if ( i >= 0 && _data[i].in ) { + if ( _comp(value, _data[i].prio) ) decrease(item, value); + if ( _comp(_data[i].prio, value) ) increase(item, value); } else push(item, value); } - /// \brief Adds \c item to the heap with priority \c value. + /// \brief Insert an item into the heap with the given priority. /// - /// Adds \c item to the heap with priority \c value. - /// \pre \c item must not be stored in the heap. + /// This function inserts the given item into the heap with the + /// given priority. + /// \param item The item to insert. + /// \param value The priority of the item. + /// \pre \e item must not be stored in the heap. void push (const Item& item, const Prio& value) { - int i=iimap[item]; + int i=_iim[item]; if ( i<0 ) { - int s=container.size(); - iimap.set( item,s ); + int s=_data.size(); + _iim.set( item,s ); store st; st.name=item; - container.push_back(st); + _data.push_back(st); i=s; } else { - container[i].parent=container[i].right_neighbor=container[i].child=-1; - container[i].degree=0; - container[i].in=true; + _data[i].parent=_data[i].right_neighbor=_data[i].child=-1; + _data[i].degree=0; + _data[i].in=true; } - container[i].prio=value; + _data[i].prio=value; - if( 0==num_items ) { head=i; minimum=i; } + if( 0==_num_items ) { _head=i; _min=i; } else { merge(i); } - minimum = find_min(); + _min = findMin(); - ++num_items; + ++_num_items; } - /// \brief Returns the item with minimum priority relative to \c Compare. + /// \brief Return the item having minimum priority. /// - /// This method returns the item with minimum priority relative to \c - /// Compare. - /// \pre The heap must be nonempty. - Item top() const { return container[minimum].name; } + /// This function returns the item having minimum priority. + /// \pre The heap must be non-empty. + Item top() const { return _data[_min].name; } - /// \brief Returns the minimum priority relative to \c Compare. + /// \brief The minimum priority. /// - /// It returns the minimum priority relative to \c Compare. - /// \pre The heap must be nonempty. - const Prio& prio() const { return container[minimum].prio; } + /// This function returns the minimum priority. + /// \pre The heap must be non-empty. + Prio prio() const { return _data[_min].prio; } - /// \brief Returns the priority of \c item. + /// \brief The priority of the given item. /// - /// It returns the priority of \c item. - /// \pre \c item must be in the heap. + /// This function returns the priority of the given item. + /// \param item The item. + /// \pre \e item must be in the heap. const Prio& operator[](const Item& item) const { - return container[iimap[item]].prio; + return _data[_iim[item]].prio; } - /// \brief Deletes the item with minimum priority relative to \c Compare. + /// \brief Remove the item having minimum priority. /// - /// This method deletes the item with minimum priority relative to \c - /// Compare from the heap. + /// This function removes the item having minimum priority. /// \pre The heap must be non-empty. void pop() { - container[minimum].in=false; + _data[_min].in=false; int head_child=-1; - if ( container[minimum].child!=-1 ) { - int child=container[minimum].child; + if ( _data[_min].child!=-1 ) { + int child=_data[_min].child; int neighb; int prev=-1; while( child!=-1 ) { - neighb=container[child].right_neighbor; - container[child].parent=-1; - container[child].right_neighbor=prev; + neighb=_data[child].right_neighbor; + _data[child].parent=-1; + _data[child].right_neighbor=prev; head_child=child; prev=child; child=neighb; @@ -214,142 +220,144 @@ } // The first case is that there are only one root. - if ( -1==container[head].right_neighbor ) { - head=head_child; + if ( -1==_data[_head].right_neighbor ) { + _head=head_child; } // The case where there are more roots. else { - if( head!=minimum ) { unlace(minimum); } - else { head=container[head].right_neighbor; } + if( _head!=_min ) { unlace(_min); } + else { _head=_data[_head].right_neighbor; } merge(head_child); } - minimum=find_min(); - --num_items; + _min=findMin(); + --_num_items; } - /// \brief Deletes \c item from the heap. + /// \brief Remove the given item from the heap. /// - /// This method deletes \c item from the heap, if \c item was already - /// stored in the heap. It is quite inefficient in Binomial heaps. + /// This function removes the given item from the heap if it is + /// already stored. + /// \param item The item to delete. + /// \pre \e item must be in the heap. void erase (const Item& item) { - int i=iimap[item]; - if ( i >= 0 && container[i].in ) { - decrease( item, container[minimum].prio-1 ); + int i=_iim[item]; + if ( i >= 0 && _data[i].in ) { + decrease( item, _data[_min].prio-1 ); pop(); } } - /// \brief Decreases the priority of \c item to \c value. + /// \brief Decrease the priority of an item to the given value. /// - /// This method decreases the priority of \c item to \c value. - /// \pre \c item must be stored in the heap with priority at least \c - /// value relative to \c Compare. + /// This function decreases the priority of an item to the given value. + /// \param item The item. + /// \param value The priority. + /// \pre \e item must be stored in the heap with priority at least \e value. void decrease (Item item, const Prio& value) { - int i=iimap[item]; + int i=_iim[item]; - if( comp( value,container[i].prio ) ) { - container[i].prio=value; + if( _comp( value,_data[i].prio ) ) { + _data[i].prio=value; - int p_loc=container[i].parent, loc=i; + int p_loc=_data[i].parent, loc=i; int parent, child, neighb; - while( -1!=p_loc && comp(container[loc].prio,container[p_loc].prio) ) { + while( -1!=p_loc && _comp(_data[loc].prio,_data[p_loc].prio) ) { // parent set for other loc_child - child=container[loc].child; + child=_data[loc].child; while( -1!=child ) { - container[child].parent=p_loc; - child=container[child].right_neighbor; + _data[child].parent=p_loc; + child=_data[child].right_neighbor; } // parent set for other p_loc_child - child=container[p_loc].child; + child=_data[p_loc].child; while( -1!=child ) { - container[child].parent=loc; - child=container[child].right_neighbor; + _data[child].parent=loc; + child=_data[child].right_neighbor; } - child=container[p_loc].child; - container[p_loc].child=container[loc].child; + child=_data[p_loc].child; + _data[p_loc].child=_data[loc].child; if( child==loc ) child=p_loc; - container[loc].child=child; + _data[loc].child=child; // left_neighb set for p_loc - if( container[loc].child!=p_loc ) { - while( container[child].right_neighbor!=loc ) - child=container[child].right_neighbor; - container[child].right_neighbor=p_loc; + if( _data[loc].child!=p_loc ) { + while( _data[child].right_neighbor!=loc ) + child=_data[child].right_neighbor; + _data[child].right_neighbor=p_loc; } // left_neighb set for loc - parent=container[p_loc].parent; - if( -1!=parent ) child=container[parent].child; - else child=head; + parent=_data[p_loc].parent; + if( -1!=parent ) child=_data[parent].child; + else child=_head; if( child!=p_loc ) { - while( container[child].right_neighbor!=p_loc ) - child=container[child].right_neighbor; - container[child].right_neighbor=loc; + while( _data[child].right_neighbor!=p_loc ) + child=_data[child].right_neighbor; + _data[child].right_neighbor=loc; } - neighb=container[p_loc].right_neighbor; - container[p_loc].right_neighbor=container[loc].right_neighbor; - container[loc].right_neighbor=neighb; + neighb=_data[p_loc].right_neighbor; + _data[p_loc].right_neighbor=_data[loc].right_neighbor; + _data[loc].right_neighbor=neighb; - container[p_loc].parent=loc; - container[loc].parent=parent; + _data[p_loc].parent=loc; + _data[loc].parent=parent; - if( -1!=parent && container[parent].child==p_loc ) - container[parent].child=loc; + if( -1!=parent && _data[parent].child==p_loc ) + _data[parent].child=loc; /*if new parent will be the first root*/ - if( head==p_loc ) - head=loc; + if( _head==p_loc ) + _head=loc; - p_loc=container[loc].parent; + p_loc=_data[loc].parent; } } - if( comp(value,container[minimum].prio) ) { - minimum=i; + if( _comp(value,_data[_min].prio) ) { + _min=i; } } - /// \brief Increases the priority of \c item to \c value. + /// \brief Increase the priority of an item to the given value. /// - /// This method sets the priority of \c item to \c value. Though - /// there is no precondition on the priority of \c item, this - /// method should be used only if it is indeed necessary to increase - /// (relative to \c Compare) the priority of \c item, because this - /// method is inefficient. + /// This function increases the priority of an item to the given value. + /// \param item The item. + /// \param value The priority. + /// \pre \e item must be stored in the heap with priority at most \e value. void increase (Item item, const Prio& value) { erase(item); push(item, value); } - - /// \brief Returns if \c item is in, has already been in, or has never - /// been in the heap. + /// \brief Return the state of an item. /// - /// This method returns PRE_HEAP if \c item has never been in the - /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP - /// otherwise. In the latter case it is possible that \c item will - /// get back to the heap again. + /// 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 + /// to the heap again. + /// \param item The item. State state(const Item &item) const { - int i=iimap[item]; + int i=_iim[item]; if( i>=0 ) { - if ( container[i].in ) i=0; + if ( _data[i].in ) i=0; else i=-2; } return State(i); } - /// \brief Sets the state of the \c item in the heap. + /// \brief Set the state of an item in the heap. /// - /// Sets the state of the \c item in the heap. It can be used to - /// manually clear the heap when it is important to achive the - /// better time complexity. + /// 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 i The item. /// \param st The state. It should not be \c IN_HEAP. void state(const Item& i, State st) { @@ -359,7 +367,7 @@ if (state(i) == IN_HEAP) { erase(i); } - iimap[i] = st; + _iim[i] = st; break; case IN_HEAP: break; @@ -367,20 +375,20 @@ } private: - int find_min() { + int findMin() { int min_loc=-1, min_val; - int x=head; + int x=_head; if( x!=-1 ) { - min_val=container[x].prio; + min_val=_data[x].prio; min_loc=x; - x=container[x].right_neighbor; + x=_data[x].right_neighbor; while( x!=-1 ) { - if( comp( container[x].prio,min_val ) ) { - min_val=container[x].prio; + if( _comp( _data[x].prio,min_val ) ) { + min_val=_data[x].prio; min_loc=x; } - x=container[x].right_neighbor; + x=_data[x].right_neighbor; } } return min_loc; @@ -389,29 +397,29 @@ void merge(int a) { interleave(a); - int x=head; + int x=_head; if( -1!=x ) { - int x_prev=-1, x_next=container[x].right_neighbor; + int x_prev=-1, x_next=_data[x].right_neighbor; while( -1!=x_next ) { - if( container[x].degree!=container[x_next].degree || ( -1!=container[x_next].right_neighbor && container[container[x_next].right_neighbor].degree==container[x].degree ) ) { + if( _data[x].degree!=_data[x_next].degree || ( -1!=_data[x_next].right_neighbor && _data[_data[x_next].right_neighbor].degree==_data[x].degree ) ) { x_prev=x; x=x_next; } else { - if( comp(container[x].prio,container[x_next].prio) ) { - container[x].right_neighbor=container[x_next].right_neighbor; + if( _comp(_data[x].prio,_data[x_next].prio) ) { + _data[x].right_neighbor=_data[x_next].right_neighbor; fuse(x_next,x); } else { - if( -1==x_prev ) { head=x_next; } + if( -1==x_prev ) { _head=x_next; } else { - container[x_prev].right_neighbor=x_next; + _data[x_prev].right_neighbor=x_next; } fuse(x,x_next); x=x_next; } } - x_next=container[x].right_neighbor; + x_next=_data[x].right_neighbor; } } } @@ -419,68 +427,68 @@ void interleave(int a) { int other=-1, head_other=-1; - while( -1!=a || -1!=head ) { + while( -1!=a || -1!=_head ) { if( -1==a ) { if( -1==head_other ) { - head_other=head; + head_other=_head; } else { - container[other].right_neighbor=head; + _data[other].right_neighbor=_head; } - head=-1; + _head=-1; } - else if( -1==head ) { + else if( -1==_head ) { if( -1==head_other ) { head_other=a; } else { - container[other].right_neighbor=a; + _data[other].right_neighbor=a; } a=-1; } else { - if( container[a].degree