[906] | 1 | /* -*- C++ -*- |
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[921] | 2 | * src/lemon/bin_heap.h - Part of LEMON, a generic C++ optimization library |
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[39] | 3 | * |
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[906] | 4 | * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 5 | * (Egervary Combinatorial Optimization Research Group, EGRES). |
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[39] | 6 | * |
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[906] | 7 | * Permission to use, modify and distribute this software is granted |
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| 8 | * provided that this copyright notice appears in all copies. For |
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| 9 | * precise terms see the accompanying LICENSE file. |
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[39] | 10 | * |
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[906] | 11 | * This software is provided "AS IS" with no warranty of any kind, |
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| 12 | * express or implied, and with no claim as to its suitability for any |
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| 13 | * purpose. |
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[39] | 14 | * |
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| 15 | */ |
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| 16 | |
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[921] | 17 | #ifndef LEMON_BIN_HEAP_H |
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| 18 | #define LEMON_BIN_HEAP_H |
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[37] | 19 | |
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[491] | 20 | ///\ingroup auxdat |
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[274] | 21 | ///\file |
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| 22 | ///\brief Binary Heap implementation. |
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[906] | 23 | ///\todo It should be documented. |
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[274] | 24 | |
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[37] | 25 | #include <vector> |
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| 26 | #include <utility> |
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| 27 | #include <functional> |
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| 28 | |
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[921] | 29 | namespace lemon { |
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[37] | 30 | |
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[430] | 31 | /// \addtogroup auxdat |
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| 32 | /// @{ |
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| 33 | |
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| 34 | /// A Binary Heap implementation. |
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[967] | 35 | |
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| 36 | ///\todo Please document... |
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| 37 | /// |
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| 38 | ///\sa FibHeap |
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| 39 | ///\sa Dijkstra |
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[172] | 40 | template <typename Item, typename Prio, typename ItemIntMap, |
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| 41 | typename Compare = std::less<Prio> > |
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[37] | 42 | class BinHeap { |
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| 43 | |
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| 44 | public: |
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[172] | 45 | typedef Item ItemType; |
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[37] | 46 | // FIXME: stl-ben nem ezt hivjak value_type -nak, hanem a kovetkezot... |
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[172] | 47 | typedef Prio PrioType; |
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| 48 | typedef std::pair<ItemType,PrioType> PairType; |
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| 49 | typedef ItemIntMap ItemIntMapType; |
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| 50 | typedef Compare PrioCompare; |
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[37] | 51 | |
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| 52 | /** |
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[172] | 53 | * Each Item element have a state associated to it. It may be "in heap", |
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[37] | 54 | * "pre heap" or "post heap". The later two are indifferent from the |
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| 55 | * heap's point of view, but may be useful to the user. |
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| 56 | * |
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[172] | 57 | * The ItemIntMap _should_ be initialized in such way, that it maps |
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[37] | 58 | * PRE_HEAP (-1) to any element to be put in the heap... |
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| 59 | */ |
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[274] | 60 | ///\todo it is used nowhere |
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| 61 | /// |
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[39] | 62 | enum state_enum { |
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[37] | 63 | IN_HEAP = 0, |
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| 64 | PRE_HEAP = -1, |
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| 65 | POST_HEAP = -2 |
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| 66 | }; |
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| 67 | |
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| 68 | private: |
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| 69 | std::vector<PairType> data; |
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| 70 | Compare comp; |
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| 71 | // FIXME: jo ez igy??? |
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[172] | 72 | ItemIntMap &iim; |
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[37] | 73 | |
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| 74 | public: |
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[967] | 75 | ///\e |
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[172] | 76 | BinHeap(ItemIntMap &_iim) : iim(_iim) {} |
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[967] | 77 | ///\e |
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[172] | 78 | BinHeap(ItemIntMap &_iim, const Compare &_comp) : comp(_comp), iim(_iim) {} |
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[37] | 79 | |
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| 80 | |
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[967] | 81 | ///\e |
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[37] | 82 | int size() const { return data.size(); } |
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[967] | 83 | ///\e |
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[41] | 84 | bool empty() const { return data.empty(); } |
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[37] | 85 | |
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| 86 | private: |
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| 87 | static int parent(int i) { return (i-1)/2; } |
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| 88 | static int second_child(int i) { return 2*i+2; } |
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[214] | 89 | bool less(const PairType &p1, const PairType &p2) const { |
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[37] | 90 | return comp(p1.second, p2.second); |
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| 91 | } |
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| 92 | |
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| 93 | int bubble_up(int hole, PairType p); |
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| 94 | int bubble_down(int hole, PairType p, int length); |
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| 95 | |
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| 96 | void move(const PairType &p, int i) { |
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| 97 | data[i] = p; |
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[172] | 98 | iim.set(p.first, i); |
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[37] | 99 | } |
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| 100 | |
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[41] | 101 | void rmidx(int h) { |
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| 102 | int n = data.size()-1; |
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| 103 | if( h>=0 && h<=n ) { |
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[172] | 104 | iim.set(data[h].first, POST_HEAP); |
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[41] | 105 | if ( h<n ) { |
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| 106 | bubble_down(h, data[n], n); |
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| 107 | } |
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| 108 | data.pop_back(); |
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| 109 | } |
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| 110 | } |
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| 111 | |
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[37] | 112 | public: |
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[967] | 113 | ///\e |
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[37] | 114 | void push(const PairType &p) { |
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| 115 | int n = data.size(); |
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| 116 | data.resize(n+1); |
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| 117 | bubble_up(n, p); |
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| 118 | } |
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[967] | 119 | ///\e |
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[172] | 120 | void push(const Item &i, const Prio &p) { push(PairType(i,p)); } |
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[37] | 121 | |
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[967] | 122 | ///\e |
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[172] | 123 | Item top() const { |
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[37] | 124 | return data[0].first; |
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| 125 | } |
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[274] | 126 | /// Returns the prio of the top element of the heap. |
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| 127 | Prio prio() const { |
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[37] | 128 | return data[0].second; |
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| 129 | } |
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| 130 | |
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[967] | 131 | ///\e |
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[37] | 132 | void pop() { |
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[41] | 133 | rmidx(0); |
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| 134 | } |
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| 135 | |
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[967] | 136 | ///\e |
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[172] | 137 | void erase(const Item &i) { |
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[221] | 138 | rmidx(iim[i]); |
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[37] | 139 | } |
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| 140 | |
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[967] | 141 | ///\e |
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[274] | 142 | Prio operator[](const Item &i) const { |
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[221] | 143 | int idx = iim[i]; |
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[37] | 144 | return data[idx].second; |
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| 145 | } |
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[274] | 146 | |
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[967] | 147 | ///\e |
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[172] | 148 | void set(const Item &i, const Prio &p) { |
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[221] | 149 | int idx = iim[i]; |
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[37] | 150 | if( idx < 0 ) { |
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[172] | 151 | push(i,p); |
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[37] | 152 | } |
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[172] | 153 | else if( comp(p, data[idx].second) ) { |
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| 154 | bubble_up(idx, PairType(i,p)); |
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[37] | 155 | } |
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| 156 | else { |
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[172] | 157 | bubble_down(idx, PairType(i,p), data.size()); |
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[37] | 158 | } |
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| 159 | } |
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| 160 | |
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[967] | 161 | ///\e |
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[172] | 162 | void decrease(const Item &i, const Prio &p) { |
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[221] | 163 | int idx = iim[i]; |
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[172] | 164 | bubble_up(idx, PairType(i,p)); |
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[37] | 165 | } |
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[967] | 166 | ///\e |
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[172] | 167 | void increase(const Item &i, const Prio &p) { |
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[221] | 168 | int idx = iim[i]; |
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[172] | 169 | bubble_down(idx, PairType(i,p), data.size()); |
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[37] | 170 | } |
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| 171 | |
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[967] | 172 | ///\e |
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[172] | 173 | state_enum state(const Item &i) const { |
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[221] | 174 | int s = iim[i]; |
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[39] | 175 | if( s>=0 ) |
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| 176 | s=0; |
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| 177 | return state_enum(s); |
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| 178 | } |
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| 179 | |
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[37] | 180 | }; // class BinHeap |
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| 181 | |
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| 182 | |
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| 183 | template <typename K, typename V, typename M, typename C> |
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| 184 | int BinHeap<K,V,M,C>::bubble_up(int hole, PairType p) { |
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| 185 | int par = parent(hole); |
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| 186 | while( hole>0 && less(p,data[par]) ) { |
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| 187 | move(data[par],hole); |
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| 188 | hole = par; |
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| 189 | par = parent(hole); |
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| 190 | } |
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| 191 | move(p, hole); |
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| 192 | return hole; |
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| 193 | } |
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| 194 | |
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| 195 | template <typename K, typename V, typename M, typename C> |
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| 196 | int BinHeap<K,V,M,C>::bubble_down(int hole, PairType p, int length) { |
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| 197 | int child = second_child(hole); |
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| 198 | while(child < length) { |
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| 199 | if( less(data[child-1], data[child]) ) { |
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| 200 | --child; |
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| 201 | } |
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| 202 | if( !less(data[child], p) ) |
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| 203 | goto ok; |
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| 204 | move(data[child], hole); |
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| 205 | hole = child; |
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| 206 | child = second_child(hole); |
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| 207 | } |
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| 208 | child--; |
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| 209 | if( child<length && less(data[child], p) ) { |
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| 210 | move(data[child], hole); |
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| 211 | hole=child; |
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| 212 | } |
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| 213 | ok: |
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| 214 | move(p, hole); |
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| 215 | return hole; |
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| 216 | } |
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| 217 | |
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[430] | 218 | ///@} |
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| 219 | |
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[921] | 220 | } // namespace lemon |
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[37] | 221 | |
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[921] | 222 | #endif // LEMON_BIN_HEAP_H |
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