klao@274: // -*- C++ -*- //
klao@274:
klao@39: /* FIXME: Copyright ...
klao@39: *
klao@39: * This implementation is heavily based on STL's heap functions and
klao@39: * the similar class by Alpar Juttner in IKTA...
klao@39: */
klao@39:
klao@39: /******
klao@39: *
klao@172: * BinHeap<ItemType, PrioType, ItemIntMap, [PrioCompare]>
klao@39: *
klao@172: * Ez az osztaly item-prioritas parok tarolasara alkalmas binaris kupacot
klao@39: * valosit meg.
klao@172: * A kupacban legfolul mindig az a par talalhato, amiben a prioritas a
klao@39: * legkisebb. (Gondolj a Dijkstra pont-tavolsag kupacara; igazabol ahhoz
klao@39: * lett keszitve...)
klao@39: *
klao@172: * Megjegyzes: a kupacos temakorokben a prioritast kulcsnak szoktak nevezni,
klao@172: * de mivel ez zavaro tud lenni a property-map-es kulcs-ertek szohasznalata
klao@172: * miatt, megprobaltunk valami semleges elnevezeseket kitalalni.
klao@39: *
klao@39: * A hasznalatahoz szukseg van egy irhato/olvashato property_map-re, ami
klao@172: * az itemekhez egy int-et tud tarolni (ezzel tudom megkeresni az illeto
klao@39: * elemet a kupacban a csokkentes es hasonlo muveletekhez).
klao@39: * A map-re csak referenciat tarol, ugy hogy a kupac elete folyan a map-nek
klao@39: * is elnie kell. (???)
klao@39: *
klao@39: * Ketfele modon hasznalhato:
klao@39: * Lusta mod:
klao@172: * set(Item, Prio) metodussal pakolunk a kupacba,
klao@39: * aztan o majd eldonti, hogy ez az elem mar benne van-e es ha igen, akkor
klao@39: * csokkentettunk-e rajta, vagy noveltunk.
klao@39: * Ehhez nagyon fontos, hogy az atadott property map inicializalva legyen
klao@39: * minden szobajovo kulcs ertekre, -1 -es ertekkel!
klao@39: * Es ilyen esetben a kulcsokrol lekerdezheto az allapotuk a state metodussal:
klao@39: * (nem jart meg a kupacban PRE_HEAP=-1, epp a kupacban van IN_HEAP=0,
klao@39: * mar kikerult a kupacbol POST_HEAP=-2).
klao@39: * Szoval ebben a modban a kupac nagyjabol hasznalhato property_map-kent, csak
klao@172: * meg meg tudja mondani a "legkisebb" prioritasu elemet. De csak nagyjabol,
klao@39: * hiszen a kupacbol kikerult elemeknek elvesz az ertekuk...
klao@39: *
klao@39: * Kozvetlen mod:
klao@172: * push(Item, Prio) metodussal belerakunk a kupacba (ha az illeto kulcs mar
klao@39: * benn volt, akkor gaz).
klao@172: * increase/decrease(Item i, Prio new_prio) metodusokkal lehet
klao@172: * novelni/csokkenteni az illeto elemhez tartozo prioritast. (Ha nem volt
klao@172: * megbenne a kupacban az illeto elem, vagy nem abba az iranyba valtoztattad
klao@39: * az erteket, amerre mondtad -- gaz).
klao@39: *
klao@39: * Termeszetesen a fenti ket modot ertelemszeruen lehet keverni.
klao@39: * Ja es mindig nagyon gaz, ha belepiszkalsz a map-be, amit a kupac
klao@39: * hasznal. :-))
klao@39: *
klao@39: *
klao@39: * Bocs, most faradt vagyok, majd egyszer leforditom. (Misi)
klao@39: *
klao@39: */
klao@39:
klao@39:
alpar@921: #ifndef LEMON_BIN_HEAP_H
alpar@921: #define LEMON_BIN_HEAP_H
klao@37:
klao@491: ///\ingroup auxdat
klao@274: ///\file
klao@274: ///\brief Binary Heap implementation.
klao@274:
klao@37: #include <vector>
klao@37: #include <utility>
klao@37: #include <functional>
klao@37:
alpar@921: namespace lemon {
klao@37:
alpar@430: /// \addtogroup auxdat
alpar@430: /// @{
alpar@430:
alpar@430: /// A Binary Heap implementation.
klao@172: template <typename Item, typename Prio, typename ItemIntMap,
klao@172: typename Compare = std::less<Prio> >
klao@37: class BinHeap {
klao@37:
klao@37: public:
klao@172: typedef Item ItemType;
klao@37: // FIXME: stl-ben nem ezt hivjak value_type -nak, hanem a kovetkezot...
klao@172: typedef Prio PrioType;
klao@172: typedef std::pair<ItemType,PrioType> PairType;
klao@172: typedef ItemIntMap ItemIntMapType;
klao@172: typedef Compare PrioCompare;
klao@37:
klao@37: /**
klao@172: * Each Item element have a state associated to it. It may be "in heap",
klao@37: * "pre heap" or "post heap". The later two are indifferent from the
klao@37: * heap's point of view, but may be useful to the user.
klao@37: *
klao@172: * The ItemIntMap _should_ be initialized in such way, that it maps
klao@37: * PRE_HEAP (-1) to any element to be put in the heap...
klao@37: */
klao@274: ///\todo it is used nowhere
klao@274: ///
klao@39: enum state_enum {
klao@37: IN_HEAP = 0,
klao@37: PRE_HEAP = -1,
klao@37: POST_HEAP = -2
klao@37: };
klao@37:
klao@37: private:
klao@37: std::vector<PairType> data;
klao@37: Compare comp;
klao@37: // FIXME: jo ez igy???
klao@172: ItemIntMap &iim;
klao@37:
klao@37: public:
klao@172: BinHeap(ItemIntMap &_iim) : iim(_iim) {}
klao@172: BinHeap(ItemIntMap &_iim, const Compare &_comp) : comp(_comp), iim(_iim) {}
klao@37:
klao@37:
klao@37: int size() const { return data.size(); }
klao@41: bool empty() const { return data.empty(); }
klao@37:
klao@37: private:
klao@37: static int parent(int i) { return (i-1)/2; }
klao@37: static int second_child(int i) { return 2*i+2; }
klao@214: bool less(const PairType &p1, const PairType &p2) const {
klao@37: return comp(p1.second, p2.second);
klao@37: }
klao@37:
klao@37: int bubble_up(int hole, PairType p);
klao@37: int bubble_down(int hole, PairType p, int length);
klao@37:
klao@37: void move(const PairType &p, int i) {
klao@37: data[i] = p;
klao@172: iim.set(p.first, i);
klao@37: }
klao@37:
klao@41: void rmidx(int h) {
klao@41: int n = data.size()-1;
klao@41: if( h>=0 && h<=n ) {
klao@172: iim.set(data[h].first, POST_HEAP);
klao@41: if ( h<n ) {
klao@41: bubble_down(h, data[n], n);
klao@41: }
klao@41: data.pop_back();
klao@41: }
klao@41: }
klao@41:
klao@37: public:
klao@37: void push(const PairType &p) {
klao@37: int n = data.size();
klao@37: data.resize(n+1);
klao@37: bubble_up(n, p);
klao@37: }
klao@172: void push(const Item &i, const Prio &p) { push(PairType(i,p)); }
klao@37:
klao@172: Item top() const {
klao@37: return data[0].first;
klao@37: }
klao@274: /// Returns the prio of the top element of the heap.
klao@274: Prio prio() const {
klao@37: return data[0].second;
klao@37: }
klao@37:
klao@37: void pop() {
klao@41: rmidx(0);
klao@41: }
klao@41:
klao@172: void erase(const Item &i) {
jacint@221: rmidx(iim[i]);
klao@37: }
klao@37:
klao@274: Prio operator[](const Item &i) const {
jacint@221: int idx = iim[i];
klao@37: return data[idx].second;
klao@37: }
klao@274:
klao@172: void set(const Item &i, const Prio &p) {
jacint@221: int idx = iim[i];
klao@37: if( idx < 0 ) {
klao@172: push(i,p);
klao@37: }
klao@172: else if( comp(p, data[idx].second) ) {
klao@172: bubble_up(idx, PairType(i,p));
klao@37: }
klao@37: else {
klao@172: bubble_down(idx, PairType(i,p), data.size());
klao@37: }
klao@37: }
klao@37:
klao@172: void decrease(const Item &i, const Prio &p) {
jacint@221: int idx = iim[i];
klao@172: bubble_up(idx, PairType(i,p));
klao@37: }
klao@172: void increase(const Item &i, const Prio &p) {
jacint@221: int idx = iim[i];
klao@172: bubble_down(idx, PairType(i,p), data.size());
klao@37: }
klao@37:
klao@172: state_enum state(const Item &i) const {
jacint@221: int s = iim[i];
klao@39: if( s>=0 )
klao@39: s=0;
klao@39: return state_enum(s);
klao@39: }
klao@39:
klao@37: }; // class BinHeap
klao@37:
klao@37:
klao@37: template <typename K, typename V, typename M, typename C>
klao@37: int BinHeap<K,V,M,C>::bubble_up(int hole, PairType p) {
klao@37: int par = parent(hole);
klao@37: while( hole>0 && less(p,data[par]) ) {
klao@37: move(data[par],hole);
klao@37: hole = par;
klao@37: par = parent(hole);
klao@37: }
klao@37: move(p, hole);
klao@37: return hole;
klao@37: }
klao@37:
klao@37: template <typename K, typename V, typename M, typename C>
klao@37: int BinHeap<K,V,M,C>::bubble_down(int hole, PairType p, int length) {
klao@37: int child = second_child(hole);
klao@37: while(child < length) {
klao@37: if( less(data[child-1], data[child]) ) {
klao@37: --child;
klao@37: }
klao@37: if( !less(data[child], p) )
klao@37: goto ok;
klao@37: move(data[child], hole);
klao@37: hole = child;
klao@37: child = second_child(hole);
klao@37: }
klao@37: child--;
klao@37: if( child<length && less(data[child], p) ) {
klao@37: move(data[child], hole);
klao@37: hole=child;
klao@37: }
klao@37: ok:
klao@37: move(p, hole);
klao@37: return hole;
klao@37: }
klao@37:
alpar@430: ///@}
alpar@430:
alpar@921: } // namespace lemon
klao@37:
klao@37: #endif // BIN_HEAP_HH