1 | #ifndef BIN_HEAP_HH |
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2 | #define BIN_HEAP_HH |
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3 | |
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4 | #include <vector> |
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5 | #include <utility> |
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6 | #include <functional> |
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7 | |
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8 | namespace marci { |
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9 | |
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10 | template <typename Key, typename Val, typename KeyIntMap, |
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11 | typename Compare = std::less<Val> > |
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12 | class BinHeap { |
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13 | |
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14 | public: |
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15 | typedef Key KeyType; |
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16 | // FIXME: stl-ben nem ezt hivjak value_type -nak, hanem a kovetkezot... |
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17 | typedef Val ValueType; |
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18 | typedef std::pair<KeyType,ValueType> PairType; |
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19 | typedef KeyIntMap KeyIntMapType; |
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20 | typedef Compare ValueCompare; |
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21 | |
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22 | /** |
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23 | * Each Key element have a state associated to it. It may be "in heap", |
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24 | * "pre heap" or "post heap". The later two are indifferent from the |
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25 | * heap's point of view, but may be useful to the user. |
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26 | * |
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27 | * The KeyIntMap _should_ be initialized in such way, that it maps |
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28 | * PRE_HEAP (-1) to any element to be put in the heap... |
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29 | */ |
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30 | |
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31 | enum state { |
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32 | IN_HEAP = 0, |
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33 | PRE_HEAP = -1, |
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34 | POST_HEAP = -2 |
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35 | }; |
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36 | |
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37 | private: |
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38 | std::vector<PairType> data; |
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39 | Compare comp; |
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40 | // FIXME: jo ez igy??? |
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41 | KeyIntMap &kim; |
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42 | |
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43 | public: |
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44 | BinHeap(KeyIntMap &_kim) : kim(_kim) {} |
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45 | BinHeap(KeyIntMap &_kim, const Compare &_comp) : comp(_comp), kim(_kim) {} |
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46 | |
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47 | |
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48 | int size() const { return data.size(); } |
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49 | bool empty() const { return size() == 0; } |
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50 | |
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51 | private: |
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52 | static int parent(int i) { return (i-1)/2; } |
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53 | static int second_child(int i) { return 2*i+2; } |
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54 | bool less(const PairType &p1, const PairType &p2) { |
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55 | return comp(p1.second, p2.second); |
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56 | } |
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57 | |
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58 | int bubble_up(int hole, PairType p); |
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59 | int bubble_down(int hole, PairType p, int length); |
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60 | |
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61 | void move(const PairType &p, int i) { |
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62 | data[i] = p; |
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63 | kim.put(p.first, i); |
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64 | } |
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65 | |
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66 | public: |
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67 | void push(const PairType &p) { |
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68 | int n = data.size(); |
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69 | data.resize(n+1); |
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70 | bubble_up(n, p); |
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71 | } |
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72 | void push(const Key &k, const Val &v) { push(PairType(k,v)); } |
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73 | |
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74 | Key top() const { |
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75 | // FIXME: test size>0 ? |
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76 | return data[0].first; |
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77 | } |
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78 | Val topValue() const { |
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79 | // FIXME: test size>0 ? |
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80 | return data[0].second; |
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81 | } |
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82 | |
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83 | void pop() { |
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84 | int n = data.size()-1; |
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85 | if ( n>0 ) { |
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86 | bubble_down(0, data[n], n); |
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87 | } |
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88 | if ( n>=0 ) { |
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89 | data.pop_back(); |
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90 | } |
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91 | } |
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92 | |
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93 | const Val get(const Key &k) const { |
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94 | int idx = kim.get(k); |
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95 | return data[idx].second; |
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96 | } |
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97 | void put(const Key &k, const Val &v) { |
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98 | int idx = kim.get(k); |
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99 | if( idx < 0 ) { |
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100 | push(k,v); |
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101 | } |
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102 | else if( comp(v, data[idx].second) ) { |
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103 | bubble_up(idx, PairType(k,v)); |
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104 | } |
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105 | else { |
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106 | bubble_down(idx, PairType(k,v), data.size()); |
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107 | } |
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108 | } |
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109 | |
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110 | void decrease(const Key &k, const Val &v) { |
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111 | int idx = kim.get(k); |
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112 | bubble_up(idx, PairType(k,v)); |
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113 | } |
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114 | void increase(const Key &k, const Val &v) { |
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115 | int idx = kim.get(k); |
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116 | bubble_down(idx, PairType(k,v), data.size()); |
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117 | } |
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118 | |
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119 | }; // class BinHeap |
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120 | |
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121 | |
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122 | template <typename K, typename V, typename M, typename C> |
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123 | int BinHeap<K,V,M,C>::bubble_up(int hole, PairType p) { |
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124 | int par = parent(hole); |
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125 | while( hole>0 && less(p,data[par]) ) { |
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126 | move(data[par],hole); |
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127 | hole = par; |
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128 | par = parent(hole); |
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129 | } |
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130 | move(p, hole); |
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131 | return hole; |
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132 | } |
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133 | |
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134 | template <typename K, typename V, typename M, typename C> |
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135 | int BinHeap<K,V,M,C>::bubble_down(int hole, PairType p, int length) { |
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136 | int child = second_child(hole); |
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137 | while(child < length) { |
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138 | if( less(data[child-1], data[child]) ) { |
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139 | --child; |
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140 | } |
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141 | if( !less(data[child], p) ) |
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142 | goto ok; |
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143 | move(data[child], hole); |
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144 | hole = child; |
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145 | child = second_child(hole); |
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146 | } |
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147 | child--; |
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148 | if( child<length && less(data[child], p) ) { |
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149 | move(data[child], hole); |
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150 | hole=child; |
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151 | } |
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152 | ok: |
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153 | move(p, hole); |
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154 | return hole; |
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155 | } |
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156 | |
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157 | } // namespace marci |
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158 | |
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159 | #endif // BIN_HEAP_HH |
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