[2038] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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[2391] | 5 | * Copyright (C) 2003-2007 |
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[2038] | 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_BUCKET_HEAP_H |
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| 20 | #define LEMON_BUCKET_HEAP_H |
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| 21 | |
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| 22 | ///\ingroup auxdat |
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| 23 | ///\file |
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| 24 | ///\brief Bucket Heap implementation. |
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| 25 | |
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| 26 | #include <vector> |
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| 27 | #include <utility> |
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| 28 | #include <functional> |
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| 29 | |
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| 30 | namespace lemon { |
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| 31 | |
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| 32 | /// \ingroup auxdat |
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[2089] | 33 | /// |
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[2038] | 34 | /// \brief A Bucket Heap implementation. |
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| 35 | /// |
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| 36 | /// This class implements the \e bucket \e heap data structure. A \e heap |
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| 37 | /// is a data structure for storing items with specified values called \e |
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| 38 | /// priorities in such a way that finding the item with minimum priority is |
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| 39 | /// efficient. The bucket heap is very simple implementation, it can store |
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[2042] | 40 | /// only integer priorities and it stores for each priority in the |
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| 41 | /// \f$ [0..C) \f$ range a list of items. So it should be used only when |
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| 42 | /// the priorities are small. It is not intended to use as dijkstra heap. |
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[2038] | 43 | /// |
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| 44 | /// \param _ItemIntMap A read and writable Item int map, used internally |
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| 45 | /// to handle the cross references. |
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| 46 | /// \param minimize If the given parameter is true then the heap gives back |
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| 47 | /// the lowest priority. |
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[2263] | 48 | template <typename _ItemIntMap, bool minimize = true > |
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[2038] | 49 | class BucketHeap { |
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| 50 | |
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| 51 | public: |
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[2263] | 52 | typedef typename _ItemIntMap::Key Item; |
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[2038] | 53 | typedef int Prio; |
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| 54 | typedef std::pair<Item, Prio> Pair; |
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| 55 | typedef _ItemIntMap ItemIntMap; |
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| 56 | |
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| 57 | /// \brief Type to represent the items states. |
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| 58 | /// |
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| 59 | /// Each Item element have a state associated to it. It may be "in heap", |
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| 60 | /// "pre heap" or "post heap". The latter two are indifferent from the |
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| 61 | /// heap's point of view, but may be useful to the user. |
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| 62 | /// |
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| 63 | /// The ItemIntMap \e should be initialized in such way that it maps |
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| 64 | /// PRE_HEAP (-1) to any element to be put in the heap... |
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| 65 | enum state_enum { |
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| 66 | IN_HEAP = 0, |
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| 67 | PRE_HEAP = -1, |
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| 68 | POST_HEAP = -2 |
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| 69 | }; |
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| 70 | |
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| 71 | public: |
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| 72 | /// \brief The constructor. |
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| 73 | /// |
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| 74 | /// The constructor. |
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| 75 | /// \param _index should be given to the constructor, since it is used |
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| 76 | /// internally to handle the cross references. The value of the map |
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| 77 | /// should be PRE_HEAP (-1) for each element. |
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| 78 | explicit BucketHeap(ItemIntMap &_index) : index(_index), minimal(0) {} |
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| 79 | |
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| 80 | /// The number of items stored in the heap. |
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| 81 | /// |
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| 82 | /// \brief Returns the number of items stored in the heap. |
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| 83 | int size() const { return data.size(); } |
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| 84 | |
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| 85 | /// \brief Checks if the heap stores no items. |
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| 86 | /// |
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| 87 | /// Returns \c true if and only if the heap stores no items. |
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| 88 | bool empty() const { return data.empty(); } |
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| 89 | |
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| 90 | /// \brief Make empty this heap. |
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| 91 | /// |
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[2050] | 92 | /// Make empty this heap. It does not change the cross reference |
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| 93 | /// map. If you want to reuse a heap what is not surely empty you |
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| 94 | /// should first clear the heap and after that you should set the |
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| 95 | /// cross reference map for each item to \c PRE_HEAP. |
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[2038] | 96 | void clear() { |
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| 97 | data.clear(); first.clear(); minimal = 0; |
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| 98 | } |
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| 99 | |
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| 100 | private: |
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| 101 | |
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| 102 | void relocate_last(int idx) { |
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[2386] | 103 | if (idx + 1 < int(data.size())) { |
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[2038] | 104 | data[idx] = data.back(); |
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| 105 | if (data[idx].prev != -1) { |
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| 106 | data[data[idx].prev].next = idx; |
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| 107 | } else { |
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| 108 | first[data[idx].value] = idx; |
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| 109 | } |
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| 110 | if (data[idx].next != -1) { |
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| 111 | data[data[idx].next].prev = idx; |
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| 112 | } |
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| 113 | index[data[idx].item] = idx; |
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| 114 | } |
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| 115 | data.pop_back(); |
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| 116 | } |
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| 117 | |
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| 118 | void unlace(int idx) { |
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| 119 | if (data[idx].prev != -1) { |
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| 120 | data[data[idx].prev].next = data[idx].next; |
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| 121 | } else { |
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| 122 | first[data[idx].value] = data[idx].next; |
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| 123 | } |
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| 124 | if (data[idx].next != -1) { |
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| 125 | data[data[idx].next].prev = data[idx].prev; |
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| 126 | } |
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| 127 | } |
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| 128 | |
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| 129 | void lace(int idx) { |
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[2386] | 130 | if (int(first.size()) <= data[idx].value) { |
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[2038] | 131 | first.resize(data[idx].value + 1, -1); |
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| 132 | } |
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| 133 | data[idx].next = first[data[idx].value]; |
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| 134 | if (data[idx].next != -1) { |
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| 135 | data[data[idx].next].prev = idx; |
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| 136 | } |
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| 137 | first[data[idx].value] = idx; |
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| 138 | data[idx].prev = -1; |
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| 139 | } |
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| 140 | |
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| 141 | public: |
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| 142 | /// \brief Insert a pair of item and priority into the heap. |
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| 143 | /// |
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| 144 | /// Adds \c p.first to the heap with priority \c p.second. |
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| 145 | /// \param p The pair to insert. |
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| 146 | void push(const Pair& p) { |
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| 147 | push(p.first, p.second); |
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| 148 | } |
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| 149 | |
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| 150 | /// \brief Insert an item into the heap with the given priority. |
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| 151 | /// |
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| 152 | /// Adds \c i to the heap with priority \c p. |
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| 153 | /// \param i The item to insert. |
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| 154 | /// \param p The priority of the item. |
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| 155 | void push(const Item &i, const Prio &p) { |
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| 156 | int idx = data.size(); |
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| 157 | index[i] = idx; |
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| 158 | data.push_back(BucketItem(i, p)); |
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| 159 | lace(idx); |
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| 160 | if (p < minimal) { |
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| 161 | minimal = p; |
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| 162 | } |
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| 163 | } |
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| 164 | |
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| 165 | /// \brief Returns the item with minimum priority. |
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| 166 | /// |
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| 167 | /// This method returns the item with minimum priority. |
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| 168 | /// \pre The heap must be nonempty. |
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| 169 | Item top() const { |
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| 170 | while (first[minimal] == -1) { |
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| 171 | ++minimal; |
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| 172 | } |
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| 173 | return data[first[minimal]].item; |
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| 174 | } |
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| 175 | |
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| 176 | /// \brief Returns the minimum priority. |
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| 177 | /// |
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| 178 | /// It returns the minimum priority. |
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| 179 | /// \pre The heap must be nonempty. |
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| 180 | Prio prio() const { |
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| 181 | while (first[minimal] == -1) { |
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| 182 | ++minimal; |
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| 183 | } |
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| 184 | return minimal; |
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| 185 | } |
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| 186 | |
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| 187 | /// \brief Deletes the item with minimum priority. |
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| 188 | /// |
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| 189 | /// This method deletes the item with minimum priority from the heap. |
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| 190 | /// \pre The heap must be non-empty. |
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| 191 | void pop() { |
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| 192 | while (first[minimal] == -1) { |
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| 193 | ++minimal; |
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| 194 | } |
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| 195 | int idx = first[minimal]; |
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| 196 | index[data[idx].item] = -2; |
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| 197 | unlace(idx); |
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| 198 | relocate_last(idx); |
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| 199 | } |
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| 200 | |
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| 201 | /// \brief Deletes \c i from the heap. |
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| 202 | /// |
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| 203 | /// This method deletes item \c i from the heap, if \c i was |
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| 204 | /// already stored in the heap. |
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| 205 | /// \param i The item to erase. |
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| 206 | void erase(const Item &i) { |
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| 207 | int idx = index[i]; |
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| 208 | index[data[idx].item] = -2; |
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| 209 | unlace(idx); |
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| 210 | relocate_last(idx); |
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| 211 | } |
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| 212 | |
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| 213 | |
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| 214 | /// \brief Returns the priority of \c i. |
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| 215 | /// |
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| 216 | /// This function returns the priority of item \c i. |
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| 217 | /// \pre \c i must be in the heap. |
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| 218 | /// \param i The item. |
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| 219 | Prio operator[](const Item &i) const { |
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| 220 | int idx = index[i]; |
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| 221 | return data[idx].value; |
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| 222 | } |
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| 223 | |
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| 224 | /// \brief \c i gets to the heap with priority \c p independently |
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| 225 | /// if \c i was already there. |
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| 226 | /// |
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| 227 | /// This method calls \ref push(\c i, \c p) if \c i is not stored |
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| 228 | /// in the heap and sets the priority of \c i to \c p otherwise. |
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| 229 | /// \param i The item. |
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| 230 | /// \param p The priority. |
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| 231 | void set(const Item &i, const Prio &p) { |
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| 232 | int idx = index[i]; |
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| 233 | if (idx < 0) { |
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| 234 | push(i,p); |
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| 235 | } else if (p > data[idx].value) { |
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| 236 | increase(i, p); |
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| 237 | } else { |
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| 238 | decrease(i, p); |
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| 239 | } |
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| 240 | } |
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| 241 | |
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| 242 | /// \brief Decreases the priority of \c i to \c p. |
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[2089] | 243 | /// |
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[2038] | 244 | /// This method decreases the priority of item \c i to \c p. |
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| 245 | /// \pre \c i must be stored in the heap with priority at least \c |
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| 246 | /// p relative to \c Compare. |
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| 247 | /// \param i The item. |
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| 248 | /// \param p The priority. |
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| 249 | void decrease(const Item &i, const Prio &p) { |
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| 250 | int idx = index[i]; |
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| 251 | unlace(idx); |
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| 252 | data[idx].value = p; |
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| 253 | if (p < minimal) { |
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| 254 | minimal = p; |
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| 255 | } |
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| 256 | lace(idx); |
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| 257 | } |
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| 258 | |
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| 259 | /// \brief Increases the priority of \c i to \c p. |
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| 260 | /// |
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| 261 | /// This method sets the priority of item \c i to \c p. |
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| 262 | /// \pre \c i must be stored in the heap with priority at most \c |
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| 263 | /// p relative to \c Compare. |
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| 264 | /// \param i The item. |
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| 265 | /// \param p The priority. |
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| 266 | void increase(const Item &i, const Prio &p) { |
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| 267 | int idx = index[i]; |
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| 268 | unlace(idx); |
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| 269 | data[idx].value = p; |
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| 270 | lace(idx); |
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| 271 | } |
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| 272 | |
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| 273 | /// \brief Returns if \c item is in, has already been in, or has |
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| 274 | /// never been in the heap. |
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| 275 | /// |
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| 276 | /// This method returns PRE_HEAP if \c item has never been in the |
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| 277 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
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| 278 | /// otherwise. In the latter case it is possible that \c item will |
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| 279 | /// get back to the heap again. |
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| 280 | /// \param i The item. |
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| 281 | state_enum state(const Item &i) const { |
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| 282 | int idx = index[i]; |
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| 283 | if (idx >= 0) idx = 0; |
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| 284 | return state_enum(idx); |
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| 285 | } |
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| 286 | |
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| 287 | /// \brief Sets the state of the \c item in the heap. |
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| 288 | /// |
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| 289 | /// Sets the state of the \c item in the heap. It can be used to |
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| 290 | /// manually clear the heap when it is important to achive the |
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| 291 | /// better time complexity. |
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| 292 | /// \param i The item. |
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| 293 | /// \param st The state. It should not be \c IN_HEAP. |
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| 294 | void state(const Item& i, state_enum st) { |
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| 295 | switch (st) { |
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| 296 | case POST_HEAP: |
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| 297 | case PRE_HEAP: |
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| 298 | if (state(i) == IN_HEAP) { |
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| 299 | erase(i); |
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| 300 | } |
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| 301 | index[i] = st; |
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| 302 | break; |
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| 303 | case IN_HEAP: |
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| 304 | break; |
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| 305 | } |
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| 306 | } |
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| 307 | |
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| 308 | private: |
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| 309 | |
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| 310 | struct BucketItem { |
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| 311 | BucketItem(const Item& _item, int _value) |
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| 312 | : item(_item), value(_value) {} |
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| 313 | |
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| 314 | Item item; |
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| 315 | int value; |
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| 316 | |
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| 317 | int prev, next; |
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| 318 | }; |
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| 319 | |
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| 320 | ItemIntMap& index; |
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| 321 | std::vector<int> first; |
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| 322 | std::vector<BucketItem> data; |
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| 323 | mutable int minimal; |
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| 324 | |
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| 325 | }; // class BucketHeap |
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| 326 | |
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| 327 | |
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[2263] | 328 | template <typename _ItemIntMap> |
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| 329 | class BucketHeap<_ItemIntMap, false> { |
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[2038] | 330 | |
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| 331 | public: |
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[2263] | 332 | typedef typename _ItemIntMap::Key Item; |
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[2038] | 333 | typedef int Prio; |
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| 334 | typedef std::pair<Item, Prio> Pair; |
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| 335 | typedef _ItemIntMap ItemIntMap; |
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| 336 | |
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| 337 | enum state_enum { |
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| 338 | IN_HEAP = 0, |
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| 339 | PRE_HEAP = -1, |
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| 340 | POST_HEAP = -2 |
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| 341 | }; |
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| 342 | |
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| 343 | public: |
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| 344 | |
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| 345 | explicit BucketHeap(ItemIntMap &_index) : index(_index), maximal(-1) {} |
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| 346 | |
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| 347 | int size() const { return data.size(); } |
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| 348 | bool empty() const { return data.empty(); } |
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| 349 | |
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| 350 | void clear() { |
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| 351 | data.clear(); first.clear(); maximal = -1; |
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| 352 | } |
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| 353 | |
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| 354 | private: |
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| 355 | |
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| 356 | void relocate_last(int idx) { |
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[2386] | 357 | if (idx + 1 != int(data.size())) { |
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[2038] | 358 | data[idx] = data.back(); |
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| 359 | if (data[idx].prev != -1) { |
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| 360 | data[data[idx].prev].next = idx; |
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| 361 | } else { |
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| 362 | first[data[idx].value] = idx; |
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| 363 | } |
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| 364 | if (data[idx].next != -1) { |
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| 365 | data[data[idx].next].prev = idx; |
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| 366 | } |
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| 367 | index[data[idx].item] = idx; |
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| 368 | } |
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| 369 | data.pop_back(); |
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| 370 | } |
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| 371 | |
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| 372 | void unlace(int idx) { |
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| 373 | if (data[idx].prev != -1) { |
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| 374 | data[data[idx].prev].next = data[idx].next; |
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| 375 | } else { |
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| 376 | first[data[idx].value] = data[idx].next; |
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| 377 | } |
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| 378 | if (data[idx].next != -1) { |
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| 379 | data[data[idx].next].prev = data[idx].prev; |
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| 380 | } |
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| 381 | } |
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| 382 | |
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| 383 | void lace(int idx) { |
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[2386] | 384 | if (int(first.size()) <= data[idx].value) { |
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[2038] | 385 | first.resize(data[idx].value + 1, -1); |
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| 386 | } |
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| 387 | data[idx].next = first[data[idx].value]; |
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| 388 | if (data[idx].next != -1) { |
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| 389 | data[data[idx].next].prev = idx; |
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| 390 | } |
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| 391 | first[data[idx].value] = idx; |
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| 392 | data[idx].prev = -1; |
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| 393 | } |
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| 394 | |
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| 395 | public: |
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| 396 | |
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| 397 | void push(const Pair& p) { |
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| 398 | push(p.first, p.second); |
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| 399 | } |
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| 400 | |
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| 401 | void push(const Item &i, const Prio &p) { |
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| 402 | int idx = data.size(); |
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| 403 | index[i] = idx; |
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| 404 | data.push_back(BucketItem(i, p)); |
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| 405 | lace(idx); |
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| 406 | if (data[idx].value > maximal) { |
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| 407 | maximal = data[idx].value; |
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| 408 | } |
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| 409 | } |
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| 410 | |
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| 411 | Item top() const { |
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| 412 | while (first[maximal] == -1) { |
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| 413 | --maximal; |
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| 414 | } |
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| 415 | return data[first[maximal]].item; |
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| 416 | } |
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| 417 | |
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| 418 | Prio prio() const { |
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| 419 | while (first[maximal] == -1) { |
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| 420 | --maximal; |
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| 421 | } |
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| 422 | return maximal; |
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| 423 | } |
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| 424 | |
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| 425 | void pop() { |
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| 426 | while (first[maximal] == -1) { |
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| 427 | --maximal; |
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| 428 | } |
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| 429 | int idx = first[maximal]; |
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| 430 | index[data[idx].item] = -2; |
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| 431 | unlace(idx); |
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| 432 | relocate_last(idx); |
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| 433 | } |
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| 434 | |
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| 435 | void erase(const Item &i) { |
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| 436 | int idx = index[i]; |
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| 437 | index[data[idx].item] = -2; |
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| 438 | unlace(idx); |
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| 439 | relocate_last(idx); |
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| 440 | } |
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| 441 | |
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| 442 | Prio operator[](const Item &i) const { |
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| 443 | int idx = index[i]; |
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| 444 | return data[idx].value; |
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| 445 | } |
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| 446 | |
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| 447 | void set(const Item &i, const Prio &p) { |
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| 448 | int idx = index[i]; |
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| 449 | if (idx < 0) { |
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| 450 | push(i,p); |
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| 451 | } else if (p > data[idx].value) { |
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| 452 | decrease(i, p); |
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| 453 | } else { |
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| 454 | increase(i, p); |
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| 455 | } |
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| 456 | } |
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| 457 | |
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| 458 | void decrease(const Item &i, const Prio &p) { |
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| 459 | int idx = index[i]; |
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| 460 | unlace(idx); |
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| 461 | data[idx].value = p; |
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| 462 | if (p > maximal) { |
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| 463 | maximal = p; |
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| 464 | } |
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| 465 | lace(idx); |
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| 466 | } |
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| 467 | |
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| 468 | void increase(const Item &i, const Prio &p) { |
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| 469 | int idx = index[i]; |
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| 470 | unlace(idx); |
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| 471 | data[idx].value = p; |
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| 472 | lace(idx); |
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| 473 | } |
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| 474 | |
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| 475 | state_enum state(const Item &i) const { |
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| 476 | int idx = index[i]; |
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| 477 | if (idx >= 0) idx = 0; |
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| 478 | return state_enum(idx); |
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| 479 | } |
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| 480 | |
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| 481 | void state(const Item& i, state_enum st) { |
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| 482 | switch (st) { |
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| 483 | case POST_HEAP: |
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| 484 | case PRE_HEAP: |
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| 485 | if (state(i) == IN_HEAP) { |
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| 486 | erase(i); |
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| 487 | } |
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| 488 | index[i] = st; |
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| 489 | break; |
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| 490 | case IN_HEAP: |
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| 491 | break; |
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| 492 | } |
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| 493 | } |
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| 494 | |
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| 495 | private: |
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| 496 | |
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| 497 | struct BucketItem { |
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| 498 | BucketItem(const Item& _item, int _value) |
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| 499 | : item(_item), value(_value) {} |
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| 500 | |
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| 501 | Item item; |
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| 502 | int value; |
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| 503 | |
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| 504 | int prev, next; |
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| 505 | }; |
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| 506 | |
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| 507 | ItemIntMap& index; |
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| 508 | std::vector<int> first; |
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| 509 | std::vector<BucketItem> data; |
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| 510 | mutable int maximal; |
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| 511 | |
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| 512 | }; // class BucketHeap |
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| 513 | |
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[2089] | 514 | /// \ingroup auxdat |
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| 515 | /// |
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| 516 | /// \brief A Simplified Bucket Heap implementation. |
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| 517 | /// |
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| 518 | /// This class implements a simplified \e bucket \e heap data |
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| 519 | /// structure. It does not provide some functionality but it faster |
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| 520 | /// and simplier data structure than the BucketHeap. The main |
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| 521 | /// difference is that the BucketHeap stores for every key a double |
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| 522 | /// linked list while this class stores just simple lists. In the |
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| 523 | /// other way it does not supports erasing each elements just the |
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| 524 | /// minimal and it does not supports key increasing, decreasing. |
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| 525 | /// |
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| 526 | /// \param _ItemIntMap A read and writable Item int map, used internally |
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| 527 | /// to handle the cross references. |
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| 528 | /// \param minimize If the given parameter is true then the heap gives back |
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| 529 | /// the lowest priority. |
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| 530 | /// |
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| 531 | /// \sa BucketHeap |
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[2263] | 532 | template <typename _ItemIntMap, bool minimize = true > |
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[2089] | 533 | class SimpleBucketHeap { |
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| 534 | |
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| 535 | public: |
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[2263] | 536 | typedef typename _ItemIntMap::Key Item; |
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[2089] | 537 | typedef int Prio; |
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| 538 | typedef std::pair<Item, Prio> Pair; |
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| 539 | typedef _ItemIntMap ItemIntMap; |
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| 540 | |
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| 541 | /// \brief Type to represent the items states. |
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| 542 | /// |
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| 543 | /// Each Item element have a state associated to it. It may be "in heap", |
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| 544 | /// "pre heap" or "post heap". The latter two are indifferent from the |
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| 545 | /// heap's point of view, but may be useful to the user. |
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| 546 | /// |
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| 547 | /// The ItemIntMap \e should be initialized in such way that it maps |
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| 548 | /// PRE_HEAP (-1) to any element to be put in the heap... |
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| 549 | enum state_enum { |
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| 550 | IN_HEAP = 0, |
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| 551 | PRE_HEAP = -1, |
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| 552 | POST_HEAP = -2 |
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| 553 | }; |
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| 554 | |
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| 555 | public: |
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| 556 | |
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| 557 | /// \brief The constructor. |
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| 558 | /// |
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| 559 | /// The constructor. |
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| 560 | /// \param _index should be given to the constructor, since it is used |
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| 561 | /// internally to handle the cross references. The value of the map |
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| 562 | /// should be PRE_HEAP (-1) for each element. |
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| 563 | explicit SimpleBucketHeap(ItemIntMap &_index) |
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| 564 | : index(_index), free(-1), num(0), minimal(0) {} |
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| 565 | |
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| 566 | /// \brief Returns the number of items stored in the heap. |
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| 567 | /// |
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| 568 | /// The number of items stored in the heap. |
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| 569 | int size() const { return num; } |
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| 570 | |
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| 571 | /// \brief Checks if the heap stores no items. |
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| 572 | /// |
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| 573 | /// Returns \c true if and only if the heap stores no items. |
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| 574 | bool empty() const { return num == 0; } |
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| 575 | |
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| 576 | /// \brief Make empty this heap. |
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| 577 | /// |
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| 578 | /// Make empty this heap. It does not change the cross reference |
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| 579 | /// map. If you want to reuse a heap what is not surely empty you |
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| 580 | /// should first clear the heap and after that you should set the |
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| 581 | /// cross reference map for each item to \c PRE_HEAP. |
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| 582 | void clear() { |
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| 583 | data.clear(); first.clear(); free = -1; num = 0; minimal = 0; |
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| 584 | } |
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| 585 | |
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| 586 | /// \brief Insert a pair of item and priority into the heap. |
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| 587 | /// |
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| 588 | /// Adds \c p.first to the heap with priority \c p.second. |
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| 589 | /// \param p The pair to insert. |
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| 590 | void push(const Pair& p) { |
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| 591 | push(p.first, p.second); |
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| 592 | } |
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| 593 | |
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| 594 | /// \brief Insert an item into the heap with the given priority. |
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| 595 | /// |
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| 596 | /// Adds \c i to the heap with priority \c p. |
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| 597 | /// \param i The item to insert. |
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| 598 | /// \param p The priority of the item. |
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| 599 | void push(const Item &i, const Prio &p) { |
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| 600 | int idx; |
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| 601 | if (free == -1) { |
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| 602 | idx = data.size(); |
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[2110] | 603 | data.push_back(BucketItem(i)); |
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[2089] | 604 | } else { |
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| 605 | idx = free; |
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| 606 | free = data[idx].next; |
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[2110] | 607 | data[idx].item = i; |
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[2089] | 608 | } |
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| 609 | index[i] = idx; |
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[2386] | 610 | if (p >= int(first.size())) first.resize(p + 1, -1); |
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[2089] | 611 | data[idx].next = first[p]; |
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| 612 | first[p] = idx; |
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| 613 | if (p < minimal) { |
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| 614 | minimal = p; |
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| 615 | } |
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| 616 | ++num; |
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| 617 | } |
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| 618 | |
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| 619 | /// \brief Returns the item with minimum priority. |
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| 620 | /// |
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| 621 | /// This method returns the item with minimum priority. |
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| 622 | /// \pre The heap must be nonempty. |
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| 623 | Item top() const { |
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| 624 | while (first[minimal] == -1) { |
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| 625 | ++minimal; |
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| 626 | } |
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| 627 | return data[first[minimal]].item; |
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| 628 | } |
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| 629 | |
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| 630 | /// \brief Returns the minimum priority. |
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| 631 | /// |
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| 632 | /// It returns the minimum priority. |
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| 633 | /// \pre The heap must be nonempty. |
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| 634 | Prio prio() const { |
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| 635 | while (first[minimal] == -1) { |
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| 636 | ++minimal; |
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| 637 | } |
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| 638 | return minimal; |
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| 639 | } |
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| 640 | |
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| 641 | /// \brief Deletes the item with minimum priority. |
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| 642 | /// |
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| 643 | /// This method deletes the item with minimum priority from the heap. |
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| 644 | /// \pre The heap must be non-empty. |
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| 645 | void pop() { |
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| 646 | while (first[minimal] == -1) { |
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| 647 | ++minimal; |
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| 648 | } |
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| 649 | int idx = first[minimal]; |
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| 650 | index[data[idx].item] = -2; |
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| 651 | first[minimal] = data[idx].next; |
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| 652 | data[idx].next = free; |
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| 653 | free = idx; |
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| 654 | --num; |
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| 655 | } |
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| 656 | |
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| 657 | /// \brief Returns the priority of \c i. |
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| 658 | /// |
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[2110] | 659 | /// This function returns the priority of item \c i. |
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| 660 | /// \warning This operator is not a constant time function |
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| 661 | /// because it scans the whole data structure to find the proper |
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| 662 | /// value. |
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[2089] | 663 | /// \pre \c i must be in the heap. |
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| 664 | /// \param i The item. |
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| 665 | Prio operator[](const Item &i) const { |
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[2110] | 666 | for (int k = 0; k < first.size(); ++k) { |
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| 667 | int idx = first[k]; |
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| 668 | while (idx != -1) { |
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| 669 | if (data[idx].item == i) { |
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| 670 | return k; |
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| 671 | } |
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| 672 | idx = data[idx].next; |
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| 673 | } |
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| 674 | } |
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| 675 | return -1; |
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[2089] | 676 | } |
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| 677 | |
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| 678 | /// \brief Returns if \c item is in, has already been in, or has |
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| 679 | /// never been in the heap. |
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| 680 | /// |
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| 681 | /// This method returns PRE_HEAP if \c item has never been in the |
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| 682 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
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| 683 | /// otherwise. In the latter case it is possible that \c item will |
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| 684 | /// get back to the heap again. |
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| 685 | /// \param i The item. |
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| 686 | state_enum state(const Item &i) const { |
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| 687 | int idx = index[i]; |
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| 688 | if (idx >= 0) idx = 0; |
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| 689 | return state_enum(idx); |
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| 690 | } |
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| 691 | |
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| 692 | private: |
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| 693 | |
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| 694 | struct BucketItem { |
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[2110] | 695 | BucketItem(const Item& _item) |
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| 696 | : item(_item) {} |
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[2089] | 697 | |
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| 698 | Item item; |
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| 699 | int next; |
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| 700 | }; |
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| 701 | |
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| 702 | ItemIntMap& index; |
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| 703 | std::vector<int> first; |
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| 704 | std::vector<BucketItem> data; |
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| 705 | int free, num; |
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| 706 | mutable int minimal; |
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| 707 | |
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| 708 | }; // class SimpleBucketHeap |
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| 709 | |
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[2263] | 710 | template <typename _ItemIntMap> |
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| 711 | class SimpleBucketHeap<_ItemIntMap, false> { |
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[2089] | 712 | |
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| 713 | public: |
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[2263] | 714 | typedef typename _ItemIntMap::Key Item; |
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[2089] | 715 | typedef int Prio; |
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| 716 | typedef std::pair<Item, Prio> Pair; |
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| 717 | typedef _ItemIntMap ItemIntMap; |
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| 718 | |
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| 719 | enum state_enum { |
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| 720 | IN_HEAP = 0, |
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| 721 | PRE_HEAP = -1, |
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| 722 | POST_HEAP = -2 |
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| 723 | }; |
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| 724 | |
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| 725 | public: |
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| 726 | |
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| 727 | explicit SimpleBucketHeap(ItemIntMap &_index) |
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| 728 | : index(_index), free(-1), num(0), maximal(0) {} |
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| 729 | |
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| 730 | int size() const { return num; } |
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| 731 | |
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| 732 | bool empty() const { return num == 0; } |
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| 733 | |
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| 734 | void clear() { |
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| 735 | data.clear(); first.clear(); free = -1; num = 0; maximal = 0; |
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| 736 | } |
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| 737 | |
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| 738 | void push(const Pair& p) { |
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| 739 | push(p.first, p.second); |
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| 740 | } |
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| 741 | |
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| 742 | void push(const Item &i, const Prio &p) { |
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| 743 | int idx; |
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| 744 | if (free == -1) { |
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| 745 | idx = data.size(); |
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[2110] | 746 | data.push_back(BucketItem(i)); |
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[2089] | 747 | } else { |
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| 748 | idx = free; |
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| 749 | free = data[idx].next; |
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[2110] | 750 | data[idx].item = i; |
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[2089] | 751 | } |
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| 752 | index[i] = idx; |
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[2386] | 753 | if (p >= int(first.size())) first.resize(p + 1, -1); |
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[2089] | 754 | data[idx].next = first[p]; |
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| 755 | first[p] = idx; |
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| 756 | if (p > maximal) { |
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| 757 | maximal = p; |
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| 758 | } |
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| 759 | ++num; |
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| 760 | } |
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| 761 | |
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| 762 | Item top() const { |
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| 763 | while (first[maximal] == -1) { |
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| 764 | --maximal; |
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| 765 | } |
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| 766 | return data[first[maximal]].item; |
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| 767 | } |
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| 768 | |
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| 769 | Prio prio() const { |
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| 770 | while (first[maximal] == -1) { |
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| 771 | --maximal; |
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| 772 | } |
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| 773 | return maximal; |
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| 774 | } |
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| 775 | |
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| 776 | void pop() { |
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| 777 | while (first[maximal] == -1) { |
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| 778 | --maximal; |
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| 779 | } |
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| 780 | int idx = first[maximal]; |
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| 781 | index[data[idx].item] = -2; |
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| 782 | first[maximal] = data[idx].next; |
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| 783 | data[idx].next = free; |
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| 784 | free = idx; |
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| 785 | --num; |
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| 786 | } |
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| 787 | |
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| 788 | Prio operator[](const Item &i) const { |
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[2110] | 789 | for (int k = 0; k < first.size(); ++k) { |
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| 790 | int idx = first[k]; |
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| 791 | while (idx != -1) { |
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| 792 | if (data[idx].item == i) { |
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| 793 | return k; |
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| 794 | } |
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| 795 | idx = data[idx].next; |
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| 796 | } |
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| 797 | } |
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| 798 | return -1; |
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[2089] | 799 | } |
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| 800 | |
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| 801 | state_enum state(const Item &i) const { |
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| 802 | int idx = index[i]; |
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| 803 | if (idx >= 0) idx = 0; |
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| 804 | return state_enum(idx); |
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| 805 | } |
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| 806 | |
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| 807 | private: |
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| 808 | |
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| 809 | struct BucketItem { |
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[2110] | 810 | BucketItem(const Item& _item) : item(_item) {} |
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[2089] | 811 | |
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| 812 | Item item; |
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| 813 | |
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| 814 | int next; |
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| 815 | }; |
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| 816 | |
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| 817 | ItemIntMap& index; |
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| 818 | std::vector<int> first; |
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| 819 | std::vector<BucketItem> data; |
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| 820 | int free, num; |
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| 821 | mutable int maximal; |
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| 822 | |
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| 823 | }; |
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| 824 | |
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[2038] | 825 | } |
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| 826 | |
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| 827 | #endif |
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