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: 
klao@37: #ifndef BIN_HEAP_HH
klao@37: #define BIN_HEAP_HH
klao@37: 
klao@37: #include <vector>
klao@37: #include <utility>
klao@37: #include <functional>
klao@37: 
alpar@114: namespace hugo {
klao@37: 
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@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@37:     bool less(const PairType &p1, const PairType &p2) {
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:       // FIXME: test size>0 ?
klao@37:       return data[0].first;
klao@37:     }
klao@172:     Prio topPrio() const {
klao@37:       // FIXME: test size>0 ?
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) {
klao@172:       rmidx(iim.get(i));
klao@37:     }
klao@37: 
klao@172:     const Prio get(const Item &i) const {
klao@172:       int idx = iim.get(i);
klao@37:       return data[idx].second;
klao@37:     }
klao@172:     void set(const Item &i, const Prio &p) {
klao@172:       int idx = iim.get(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) {
klao@172:       int idx = iim.get(i);
klao@172:       bubble_up(idx, PairType(i,p));
klao@37:     }
klao@172:     void increase(const Item &i, const Prio &p) {
klao@172:       int idx = iim.get(i);
klao@172:       bubble_down(idx, PairType(i,p), data.size());
klao@37:     }
klao@37: 
klao@172:     state_enum state(const Item &i) const {
klao@172:       int s = iim.get(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@114: } // namespace hugo
klao@37: 
klao@37: #endif // BIN_HEAP_HH