src/include/bin_heap.hh
author marci
Fri, 06 Feb 2004 11:45:47 +0000
changeset 67 5f86199dcf3e
parent 39 28b0d751d29f
child 114 bb07dd5b2d67
permissions -rw-r--r--
.
klao@39
     1
/* FIXME: Copyright ... 
klao@39
     2
 *
klao@39
     3
 * This implementation is heavily based on STL's heap functions and
klao@39
     4
 * the similar class by Alpar Juttner in IKTA...
klao@39
     5
 */
klao@39
     6
klao@39
     7
/******
klao@39
     8
 *
klao@39
     9
 * BinHeap<KeyType, ValueType, KeyIntMap, [ValueCompare]>
klao@39
    10
 *
klao@39
    11
 * Ez az osztaly kulcs-ertek parok tarolasara alkalmas binaris kupacot
klao@39
    12
 * valosit meg.
klao@39
    13
 * A kupacban legfolul mindig az a par talalhato, amiben az _ertek_ a
klao@39
    14
 * legkisebb. (Gondolj a Dijkstra pont-tavolsag kupacara; igazabol ahhoz
klao@39
    15
 * lett keszitve...)
klao@39
    16
 *
klao@39
    17
 * Megjegyzes: egy kicsit gyanus nekem, hogy a kupacos temakorben nem
klao@39
    18
 * azt hivjak kulcsnak, amit most en annak nevezek. :) En olyan 
klao@39
    19
 * property_map -os ertelemben hasznalom.
klao@39
    20
 *
klao@39
    21
 * A hasznalatahoz szukseg van egy irhato/olvashato property_map-re, ami
klao@39
    22
 * a kulcsokhoz egy int-et tud tarolni (ezzel tudom megkeresni az illeto
klao@39
    23
 * elemet a kupacban a csokkentes es hasonlo muveletekhez).
klao@39
    24
 * A map-re csak referenciat tarol, ugy hogy a kupac elete folyan a map-nek
klao@39
    25
 * is elnie kell. (???)
klao@39
    26
 *
klao@39
    27
 * Ketfele modon hasznalhato:
klao@39
    28
 * Lusta mod:
klao@39
    29
 * put(Key, Value) metodussal pakolunk a kupacba,
klao@39
    30
 * aztan o majd eldonti, hogy ez az elem mar benne van-e es ha igen, akkor
klao@39
    31
 * csokkentettunk-e rajta, vagy noveltunk.
klao@39
    32
 * Ehhez nagyon fontos, hogy az atadott property map inicializalva legyen
klao@39
    33
 * minden szobajovo kulcs ertekre, -1 -es ertekkel!
klao@39
    34
 * Es ilyen esetben a kulcsokrol lekerdezheto az allapotuk a state metodussal:
klao@39
    35
 * (nem jart meg a kupacban PRE_HEAP=-1, epp a kupacban van IN_HEAP=0,
klao@39
    36
 *  mar kikerult a kupacbol POST_HEAP=-2).
klao@39
    37
 * Szoval ebben a modban a kupac nagyjabol hasznalhato property_map-kent, csak
klao@39
    38
 * meg meg tudja mondani a "legkisebb" erteku elemet. De csak nagyjabol,
klao@39
    39
 * hiszen a kupacbol kikerult elemeknek elvesz az ertekuk...
klao@39
    40
 *
klao@39
    41
 * Kozvetlen mod:
klao@39
    42
 * push(Key, Value) metodussal belerakunk a kupacba (ha az illeto kulcs mar
klao@39
    43
 * benn volt, akkor gaz).
klao@39
    44
 * increase/decrease(Key k, Value new_value) metodusokkal lehet
klao@39
    45
 * novelni/csokkenteni az illeto kulcshoz tartozo erteket. (Ha nem volt meg
klao@39
    46
 * benne a kupacban az illeto kulcs, vagy nem abba az iranyba valtoztattad
klao@39
    47
 * az erteket, amerre mondtad -- gaz).
klao@39
    48
 *
klao@39
    49
 * Termeszetesen a fenti ket modot ertelemszeruen lehet keverni.
klao@39
    50
 * Ja es mindig nagyon gaz, ha belepiszkalsz a map-be, amit a kupac
klao@39
    51
 * hasznal. :-))
klao@39
    52
 *
klao@39
    53
 *
klao@39
    54
 * Bocs, most faradt vagyok, majd egyszer leforditom. (Misi)
klao@39
    55
 *
klao@39
    56
 */
klao@39
    57
klao@39
    58
klao@37
    59
#ifndef BIN_HEAP_HH
klao@37
    60
#define BIN_HEAP_HH
klao@37
    61
klao@37
    62
#include <vector>
klao@37
    63
#include <utility>
klao@37
    64
#include <functional>
klao@37
    65
klao@37
    66
namespace marci {
klao@37
    67
klao@37
    68
  template <typename Key, typename Val, typename KeyIntMap,
klao@37
    69
	    typename Compare = std::less<Val> >
klao@37
    70
  class BinHeap {
klao@37
    71
klao@37
    72
  public:
klao@37
    73
    typedef Key	             KeyType;
klao@37
    74
    // FIXME: stl-ben nem ezt hivjak value_type -nak, hanem a kovetkezot...
klao@37
    75
    typedef Val              ValueType;
klao@37
    76
    typedef std::pair<KeyType,ValueType>     PairType;
klao@37
    77
    typedef KeyIntMap        KeyIntMapType;
klao@37
    78
    typedef Compare          ValueCompare;
klao@37
    79
klao@37
    80
    /**
klao@37
    81
     * Each Key element have a state associated to it. It may be "in heap",
klao@37
    82
     * "pre heap" or "post heap". The later two are indifferent from the
klao@37
    83
     * heap's point of view, but may be useful to the user.
klao@37
    84
     *
klao@37
    85
     * The KeyIntMap _should_ be initialized in such way, that it maps
klao@37
    86
     * PRE_HEAP (-1) to any element to be put in the heap...
klao@37
    87
     */
klao@39
    88
    enum state_enum {
klao@37
    89
      IN_HEAP = 0,
klao@37
    90
      PRE_HEAP = -1,
klao@37
    91
      POST_HEAP = -2
klao@37
    92
    };
klao@37
    93
klao@37
    94
  private:
klao@37
    95
    std::vector<PairType> data;
klao@37
    96
    Compare comp;
klao@37
    97
    // FIXME: jo ez igy???
klao@37
    98
    KeyIntMap &kim;
klao@37
    99
klao@37
   100
  public:
klao@37
   101
    BinHeap(KeyIntMap &_kim) : kim(_kim) {}
klao@37
   102
    BinHeap(KeyIntMap &_kim, const Compare &_comp) : comp(_comp), kim(_kim) {}
klao@37
   103
klao@37
   104
klao@37
   105
    int size() const { return data.size(); }
klao@41
   106
    bool empty() const { return data.empty(); }
klao@37
   107
klao@37
   108
  private:
klao@37
   109
    static int parent(int i) { return (i-1)/2; }
klao@37
   110
    static int second_child(int i) { return 2*i+2; }
klao@37
   111
    bool less(const PairType &p1, const PairType &p2) {
klao@37
   112
      return comp(p1.second, p2.second);
klao@37
   113
    }
klao@37
   114
klao@37
   115
    int bubble_up(int hole, PairType p);
klao@37
   116
    int bubble_down(int hole, PairType p, int length);
klao@37
   117
klao@37
   118
    void move(const PairType &p, int i) {
klao@37
   119
      data[i] = p;
klao@37
   120
      kim.put(p.first, i);
klao@37
   121
    }
klao@37
   122
klao@41
   123
    void rmidx(int h) {
klao@41
   124
      int n = data.size()-1;
klao@41
   125
      if( h>=0 && h<=n ) {
klao@41
   126
	kim.put(data[h].first, POST_HEAP);
klao@41
   127
	if ( h<n ) {
klao@41
   128
	  bubble_down(h, data[n], n);
klao@41
   129
	}
klao@41
   130
	data.pop_back();
klao@41
   131
      }
klao@41
   132
    }
klao@41
   133
klao@37
   134
  public:
klao@37
   135
    void push(const PairType &p) {
klao@37
   136
      int n = data.size();
klao@37
   137
      data.resize(n+1);
klao@37
   138
      bubble_up(n, p);
klao@37
   139
    }
klao@37
   140
    void push(const Key &k, const Val &v) { push(PairType(k,v)); }
klao@37
   141
klao@37
   142
    Key top() const {
klao@37
   143
      // FIXME: test size>0 ?
klao@37
   144
      return data[0].first;
klao@37
   145
    }
klao@37
   146
    Val topValue() const {
klao@37
   147
      // FIXME: test size>0 ?
klao@37
   148
      return data[0].second;
klao@37
   149
    }
klao@37
   150
klao@37
   151
    void pop() {
klao@41
   152
      rmidx(0);
klao@41
   153
    }
klao@41
   154
klao@41
   155
    void erase(const Key &k) {
klao@41
   156
      rmidx(kim.get(k));
klao@37
   157
    }
klao@37
   158
klao@37
   159
    const Val get(const Key &k) const {
klao@37
   160
      int idx = kim.get(k);
klao@37
   161
      return data[idx].second;
klao@37
   162
    }
klao@37
   163
    void put(const Key &k, const Val &v) {
klao@37
   164
      int idx = kim.get(k);
klao@37
   165
      if( idx < 0 ) {
klao@37
   166
	push(k,v);
klao@37
   167
      }
klao@37
   168
      else if( comp(v, data[idx].second) ) {
klao@37
   169
	bubble_up(idx, PairType(k,v));
klao@37
   170
      }
klao@37
   171
      else {
klao@37
   172
	bubble_down(idx, PairType(k,v), data.size());
klao@37
   173
      }
klao@37
   174
    }
klao@37
   175
klao@37
   176
    void decrease(const Key &k, const Val &v) {
klao@37
   177
      int idx = kim.get(k);
klao@37
   178
      bubble_up(idx, PairType(k,v));
klao@37
   179
    }
klao@37
   180
    void increase(const Key &k, const Val &v) {
klao@37
   181
      int idx = kim.get(k);
klao@37
   182
      bubble_down(idx, PairType(k,v), data.size());
klao@37
   183
    }
klao@37
   184
klao@39
   185
    state_enum state(const Key &k) const {
klao@39
   186
      int s = kim.get(k);
klao@39
   187
      if( s>=0 )
klao@39
   188
	s=0;
klao@39
   189
      return state_enum(s);
klao@39
   190
    }
klao@39
   191
klao@37
   192
  }; // class BinHeap
klao@37
   193
klao@37
   194
  
klao@37
   195
  template <typename K, typename V, typename M, typename C>
klao@37
   196
  int BinHeap<K,V,M,C>::bubble_up(int hole, PairType p) {
klao@37
   197
    int par = parent(hole);
klao@37
   198
    while( hole>0 && less(p,data[par]) ) {
klao@37
   199
      move(data[par],hole);
klao@37
   200
      hole = par;
klao@37
   201
      par = parent(hole);
klao@37
   202
    }
klao@37
   203
    move(p, hole);
klao@37
   204
    return hole;
klao@37
   205
  }
klao@37
   206
klao@37
   207
  template <typename K, typename V, typename M, typename C>
klao@37
   208
  int BinHeap<K,V,M,C>::bubble_down(int hole, PairType p, int length) {
klao@37
   209
    int child = second_child(hole);
klao@37
   210
    while(child < length) {
klao@37
   211
      if( less(data[child-1], data[child]) ) {
klao@37
   212
	--child;
klao@37
   213
      }
klao@37
   214
      if( !less(data[child], p) )
klao@37
   215
	goto ok;
klao@37
   216
      move(data[child], hole);
klao@37
   217
      hole = child;
klao@37
   218
      child = second_child(hole);
klao@37
   219
    }
klao@37
   220
    child--;
klao@37
   221
    if( child<length && less(data[child], p) ) {
klao@37
   222
      move(data[child], hole);
klao@37
   223
      hole=child;
klao@37
   224
    }
klao@37
   225
  ok:
klao@37
   226
    move(p, hole);
klao@37
   227
    return hole;
klao@37
   228
  }
klao@37
   229
klao@37
   230
} // namespace marci
klao@37
   231
klao@37
   232
#endif // BIN_HEAP_HH