diff options
Diffstat (limited to 'extern/quadriflow/3rd/lemon-1.3.1/lemon/pairing_heap.h')
| -rw-r--r-- | extern/quadriflow/3rd/lemon-1.3.1/lemon/pairing_heap.h | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/extern/quadriflow/3rd/lemon-1.3.1/lemon/pairing_heap.h b/extern/quadriflow/3rd/lemon-1.3.1/lemon/pairing_heap.h new file mode 100644 index 00000000000..da6ebcb1552 --- /dev/null +++ b/extern/quadriflow/3rd/lemon-1.3.1/lemon/pairing_heap.h @@ -0,0 +1,474 @@ +/* -*- 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 + * purpose. + * + */ + +#ifndef LEMON_PAIRING_HEAP_H +#define LEMON_PAIRING_HEAP_H + +///\file +///\ingroup heaps +///\brief Pairing heap implementation. + +#include <vector> +#include <utility> +#include <functional> +#include <lemon/math.h> + +namespace lemon { + + /// \ingroup heaps + /// + ///\brief Pairing Heap. + /// + /// This class implements the \e pairing \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 pairing heap. In case of many calls of these operations, + /// it is better to use other heap structure, e.g. \ref BinHeap + /// "binary heap". + /// + /// \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>. +#ifdef DOXYGEN + template <typename PR, typename IM, typename CMP> +#else + template <typename PR, typename IM, typename CMP = std::less<PR> > +#endif + class PairingHeap { + public: + /// 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; + /// 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 (<tt>-1</tt>) 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<store> _data; + int _min; + ItemIntMap &_iim; + Compare _comp; + int _num_items; + + public: + /// \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 (<tt>-1</tt>) for each item. + explicit PairingHeap(ItemIntMap &map) + : _min(0), _iim(map), _num_items(0) {} + + /// \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 (<tt>-1</tt>) for each item. + /// \param comp The function object used for comparing the priorities. + PairingHeap(ItemIntMap &map, const Compare &comp) + : _min(0), _iim(map), _comp(comp), _num_items(0) {} + + /// \brief The number of items stored in the heap. + /// + /// This function returns the number of items stored in the heap. + int size() const { return _num_items; } + + /// \brief Check if the heap is empty. + /// + /// This function returns \c true if the heap is empty. + bool empty() const { return _num_items==0; } + + /// \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 + /// for each item. + void clear() { + _data.clear(); + _min = 0; + _num_items = 0; + } + + /// \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 item The item. + /// \param value The priority. + void set (const Item& item, const Prio& 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 Insert an item into the heap with the given priority. + /// + /// 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=_iim[item]; + if( i<0 ) { + int s=_data.size(); + _iim.set(item, s); + store st; + st.name=item; + _data.push_back(st); + i=s; + } else { + _data[i].parent=_data[i].child=-1; + _data[i].left_child=false; + _data[i].degree=0; + _data[i].in=true; + } + + _data[i].prio=value; + + if ( _num_items!=0 ) { + if ( _comp( value, _data[_min].prio) ) { + fuse(i,_min); + _min=i; + } + else fuse(_min,i); + } + else _min=i; + + ++_num_items; + } + + /// \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 _data[_min].name; } + + /// \brief The minimum priority. + /// + /// This function returns the minimum priority. + /// \pre The heap must be non-empty. + const Prio& prio() const { return _data[_min].prio; } + + /// \brief The priority of the given item. + /// + /// 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 _data[_iim[item]].prio; + } + + /// \brief Remove the item having minimum priority. + /// + /// This function removes the item having minimum priority. + /// \pre The heap must be non-empty. + void pop() { + std::vector<int> trees; + int i=0, child_right = 0; + _data[_min].in=false; + + if( -1!=_data[_min].child ) { + i=_data[_min].child; + trees.push_back(i); + _data[i].parent = -1; + _data[_min].child = -1; + + int ch=-1; + while( _data[i].child!=-1 ) { + ch=_data[i].child; + if( _data[ch].left_child && i==_data[ch].parent ) { + break; + } else { + if( _data[ch].left_child ) { + child_right=_data[ch].parent; + _data[ch].parent = i; + --_data[i].degree; + } + else { + child_right=ch; + _data[i].child=-1; + _data[i].degree=0; + } + _data[child_right].parent = -1; + trees.push_back(child_right); + i = child_right; + } + } + + int num_child = trees.size(); + int other; + for( i=0; i<num_child-1; i+=2 ) { + if ( !_comp(_data[trees[i]].prio, _data[trees[i+1]].prio) ) { + other=trees[i]; + trees[i]=trees[i+1]; + trees[i+1]=other; + } + fuse( trees[i], trees[i+1] ); + } + + i = (0==(num_child % 2)) ? num_child-2 : num_child-1; + while(i>=2) { + if ( _comp(_data[trees[i]].prio, _data[trees[i-2]].prio) ) { + other=trees[i]; + trees[i]=trees[i-2]; + trees[i-2]=other; + } + fuse( trees[i-2], trees[i] ); + i-=2; + } + _min = trees[0]; + } + else { + _min = _data[_min].child; + } + + if (_min >= 0) _data[_min].left_child = false; + --_num_items; + } + + /// \brief Remove the given item from the heap. + /// + /// 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=_iim[item]; + if ( i>=0 && _data[i].in ) { + decrease( item, _data[_min].prio-1 ); + pop(); + } + } + + /// \brief Decrease the priority of an item to the given value. + /// + /// 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=_iim[item]; + _data[i].prio=value; + int p=_data[i].parent; + + if( _data[i].left_child && i!=_data[p].child ) { + p=_data[p].parent; + } + + if ( p!=-1 && _comp(value,_data[p].prio) ) { + cut(i,p); + if ( _comp(_data[_min].prio,value) ) { + fuse(_min,i); + } else { + fuse(i,_min); + _min=i; + } + } + } + + /// \brief Increase the priority of an item to the given value. + /// + /// 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 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 + /// to the heap again. + /// \param item The item. + State state(const Item &item) const { + int i=_iim[item]; + if( i>=0 ) { + if( _data[i].in ) i=0; + else i=-2; + } + return State(i); + } + + /// \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 i The item. + /// \param st The state. It should not be \c IN_HEAP. + void state(const Item& i, State st) { + switch (st) { + case POST_HEAP: + case PRE_HEAP: + if (state(i) == IN_HEAP) erase(i); + _iim[i]=st; + break; + case IN_HEAP: + break; + } + } + + private: + + void cut(int a, int b) { + int child_a; + switch (_data[a].degree) { + case 2: + child_a = _data[_data[a].child].parent; + if( _data[a].left_child ) { + _data[child_a].left_child=true; + _data[b].child=child_a; + _data[child_a].parent=_data[a].parent; + } + else { + _data[child_a].left_child=false; + _data[child_a].parent=b; + if( a!=_data[b].child ) + _data[_data[b].child].parent=child_a; + else + _data[b].child=child_a; + } + --_data[a].degree; + _data[_data[a].child].parent=a; + break; + + case 1: + child_a = _data[a].child; + if( !_data[child_a].left_child ) { + --_data[a].degree; + if( _data[a].left_child ) { + _data[child_a].left_child=true; + _data[child_a].parent=_data[a].parent; + _data[b].child=child_a; + } + else { + _data[child_a].left_child=false; + _data[child_a].parent=b; + if( a!=_data[b].child ) + _data[_data[b].child].parent=child_a; + else + _data[b].child=child_a; + } + _data[a].child=-1; + } + else { + --_data[b].degree; + if( _data[a].left_child ) { + _data[b].child = + (1==_data[b].degree) ? _data[a].parent : -1; + } else { + if (1==_data[b].degree) + _data[_data[b].child].parent=b; + else + _data[b].child=-1; + } + } + break; + + case 0: + --_data[b].degree; + if( _data[a].left_child ) { + _data[b].child = + (0!=_data[b].degree) ? _data[a].parent : -1; + } else { + if( 0!=_data[b].degree ) + _data[_data[b].child].parent=b; + else + _data[b].child=-1; + } + break; + } + _data[a].parent=-1; + _data[a].left_child=false; + } + + void fuse(int a, int b) { + int child_a = _data[a].child; + int child_b = _data[b].child; + _data[a].child=b; + _data[b].parent=a; + _data[b].left_child=true; + + if( -1!=child_a ) { + _data[b].child=child_a; + _data[child_a].parent=b; + _data[child_a].left_child=false; + ++_data[b].degree; + + if( -1!=child_b ) { + _data[b].child=child_b; + _data[child_b].parent=child_a; + } + } + else { ++_data[a].degree; } + } + + class store { + friend class PairingHeap; + + Item name; + int parent; + int child; + bool left_child; + int degree; + bool in; + Prio prio; + + store() : parent(-1), child(-1), left_child(false), degree(0), in(true) {} + }; + }; + +} //namespace lemon + +#endif //LEMON_PAIRING_HEAP_H + |