[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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[2553] | 5 | * Copyright (C) 2003-2008 |
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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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[2547] | 52 | /// \e |
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[2263] | 53 | typedef typename _ItemIntMap::Key Item; |
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[2547] | 54 | /// \e |
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[2038] | 55 | typedef int Prio; |
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[2547] | 56 | /// \e |
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[2038] | 57 | typedef std::pair<Item, Prio> Pair; |
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[2547] | 58 | /// \e |
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[2038] | 59 | typedef _ItemIntMap ItemIntMap; |
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| 60 | |
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| 61 | /// \brief Type to represent the items states. |
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| 62 | /// |
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| 63 | /// Each Item element have a state associated to it. It may be "in heap", |
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| 64 | /// "pre heap" or "post heap". The latter two are indifferent from the |
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| 65 | /// heap's point of view, but may be useful to the user. |
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| 66 | /// |
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| 67 | /// The ItemIntMap \e should be initialized in such way that it maps |
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| 68 | /// PRE_HEAP (-1) to any element to be put in the heap... |
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[2547] | 69 | enum State { |
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[2038] | 70 | IN_HEAP = 0, |
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| 71 | PRE_HEAP = -1, |
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| 72 | POST_HEAP = -2 |
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| 73 | }; |
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| 74 | |
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| 75 | public: |
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| 76 | /// \brief The constructor. |
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| 77 | /// |
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| 78 | /// The constructor. |
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| 79 | /// \param _index should be given to the constructor, since it is used |
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| 80 | /// internally to handle the cross references. The value of the map |
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| 81 | /// should be PRE_HEAP (-1) for each element. |
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| 82 | explicit BucketHeap(ItemIntMap &_index) : index(_index), minimal(0) {} |
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| 83 | |
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| 84 | /// The number of items stored in the heap. |
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| 85 | /// |
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| 86 | /// \brief Returns the number of items stored in the heap. |
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| 87 | int size() const { return data.size(); } |
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| 88 | |
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| 89 | /// \brief Checks if the heap stores no items. |
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| 90 | /// |
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| 91 | /// Returns \c true if and only if the heap stores no items. |
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| 92 | bool empty() const { return data.empty(); } |
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| 93 | |
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| 94 | /// \brief Make empty this heap. |
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| 95 | /// |
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[2050] | 96 | /// Make empty this heap. It does not change the cross reference |
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| 97 | /// map. If you want to reuse a heap what is not surely empty you |
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| 98 | /// should first clear the heap and after that you should set the |
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| 99 | /// cross reference map for each item to \c PRE_HEAP. |
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[2038] | 100 | void clear() { |
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| 101 | data.clear(); first.clear(); minimal = 0; |
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| 102 | } |
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| 103 | |
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| 104 | private: |
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| 105 | |
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| 106 | void relocate_last(int idx) { |
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[2386] | 107 | if (idx + 1 < int(data.size())) { |
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[2038] | 108 | data[idx] = data.back(); |
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| 109 | if (data[idx].prev != -1) { |
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| 110 | data[data[idx].prev].next = idx; |
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| 111 | } else { |
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| 112 | first[data[idx].value] = idx; |
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| 113 | } |
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| 114 | if (data[idx].next != -1) { |
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| 115 | data[data[idx].next].prev = idx; |
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| 116 | } |
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| 117 | index[data[idx].item] = idx; |
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| 118 | } |
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| 119 | data.pop_back(); |
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| 120 | } |
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| 121 | |
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| 122 | void unlace(int idx) { |
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| 123 | if (data[idx].prev != -1) { |
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| 124 | data[data[idx].prev].next = data[idx].next; |
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| 125 | } else { |
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| 126 | first[data[idx].value] = data[idx].next; |
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| 127 | } |
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| 128 | if (data[idx].next != -1) { |
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| 129 | data[data[idx].next].prev = data[idx].prev; |
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| 130 | } |
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| 131 | } |
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| 132 | |
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| 133 | void lace(int idx) { |
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[2386] | 134 | if (int(first.size()) <= data[idx].value) { |
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[2038] | 135 | first.resize(data[idx].value + 1, -1); |
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| 136 | } |
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| 137 | data[idx].next = first[data[idx].value]; |
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| 138 | if (data[idx].next != -1) { |
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| 139 | data[data[idx].next].prev = idx; |
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| 140 | } |
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| 141 | first[data[idx].value] = idx; |
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| 142 | data[idx].prev = -1; |
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| 143 | } |
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| 144 | |
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| 145 | public: |
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| 146 | /// \brief Insert a pair of item and priority into the heap. |
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| 147 | /// |
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| 148 | /// Adds \c p.first to the heap with priority \c p.second. |
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| 149 | /// \param p The pair to insert. |
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| 150 | void push(const Pair& p) { |
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| 151 | push(p.first, p.second); |
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| 152 | } |
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| 153 | |
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| 154 | /// \brief Insert an item into the heap with the given priority. |
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| 155 | /// |
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| 156 | /// Adds \c i to the heap with priority \c p. |
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| 157 | /// \param i The item to insert. |
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| 158 | /// \param p The priority of the item. |
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| 159 | void push(const Item &i, const Prio &p) { |
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| 160 | int idx = data.size(); |
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| 161 | index[i] = idx; |
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| 162 | data.push_back(BucketItem(i, p)); |
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| 163 | lace(idx); |
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| 164 | if (p < minimal) { |
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| 165 | minimal = p; |
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| 166 | } |
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| 167 | } |
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| 168 | |
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| 169 | /// \brief Returns the item with minimum priority. |
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| 170 | /// |
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| 171 | /// This method returns the item with minimum priority. |
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| 172 | /// \pre The heap must be nonempty. |
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| 173 | Item top() const { |
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| 174 | while (first[minimal] == -1) { |
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| 175 | ++minimal; |
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| 176 | } |
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| 177 | return data[first[minimal]].item; |
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| 178 | } |
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| 179 | |
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| 180 | /// \brief Returns the minimum priority. |
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| 181 | /// |
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| 182 | /// It returns the minimum priority. |
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| 183 | /// \pre The heap must be nonempty. |
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| 184 | Prio prio() const { |
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| 185 | while (first[minimal] == -1) { |
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| 186 | ++minimal; |
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| 187 | } |
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| 188 | return minimal; |
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| 189 | } |
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| 190 | |
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| 191 | /// \brief Deletes the item with minimum priority. |
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| 192 | /// |
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| 193 | /// This method deletes the item with minimum priority from the heap. |
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| 194 | /// \pre The heap must be non-empty. |
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| 195 | void pop() { |
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| 196 | while (first[minimal] == -1) { |
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| 197 | ++minimal; |
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| 198 | } |
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| 199 | int idx = first[minimal]; |
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| 200 | index[data[idx].item] = -2; |
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| 201 | unlace(idx); |
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| 202 | relocate_last(idx); |
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| 203 | } |
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| 204 | |
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| 205 | /// \brief Deletes \c i from the heap. |
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| 206 | /// |
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| 207 | /// This method deletes item \c i from the heap, if \c i was |
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| 208 | /// already stored in the heap. |
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| 209 | /// \param i The item to erase. |
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| 210 | void erase(const Item &i) { |
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| 211 | int idx = index[i]; |
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| 212 | index[data[idx].item] = -2; |
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| 213 | unlace(idx); |
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| 214 | relocate_last(idx); |
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| 215 | } |
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| 216 | |
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| 217 | |
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| 218 | /// \brief Returns the priority of \c i. |
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| 219 | /// |
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| 220 | /// This function returns the priority of item \c i. |
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| 221 | /// \pre \c i must be in the heap. |
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| 222 | /// \param i The item. |
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| 223 | Prio operator[](const Item &i) const { |
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| 224 | int idx = index[i]; |
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| 225 | return data[idx].value; |
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| 226 | } |
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| 227 | |
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| 228 | /// \brief \c i gets to the heap with priority \c p independently |
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| 229 | /// if \c i was already there. |
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| 230 | /// |
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| 231 | /// This method calls \ref push(\c i, \c p) if \c i is not stored |
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| 232 | /// in the heap and sets the priority of \c i to \c p otherwise. |
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| 233 | /// \param i The item. |
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| 234 | /// \param p The priority. |
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| 235 | void set(const Item &i, const Prio &p) { |
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| 236 | int idx = index[i]; |
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| 237 | if (idx < 0) { |
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| 238 | push(i,p); |
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| 239 | } else if (p > data[idx].value) { |
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| 240 | increase(i, p); |
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| 241 | } else { |
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| 242 | decrease(i, p); |
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| 243 | } |
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| 244 | } |
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| 245 | |
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| 246 | /// \brief Decreases the priority of \c i to \c p. |
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[2089] | 247 | /// |
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[2038] | 248 | /// This method decreases the priority of item \c i to \c p. |
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| 249 | /// \pre \c i must be stored in the heap with priority at least \c |
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| 250 | /// p relative to \c Compare. |
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| 251 | /// \param i The item. |
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| 252 | /// \param p The priority. |
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| 253 | void decrease(const Item &i, const Prio &p) { |
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| 254 | int idx = index[i]; |
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| 255 | unlace(idx); |
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| 256 | data[idx].value = p; |
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| 257 | if (p < minimal) { |
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| 258 | minimal = p; |
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| 259 | } |
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| 260 | lace(idx); |
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| 261 | } |
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| 262 | |
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| 263 | /// \brief Increases the priority of \c i to \c p. |
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| 264 | /// |
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| 265 | /// This method sets the priority of item \c i to \c p. |
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| 266 | /// \pre \c i must be stored in the heap with priority at most \c |
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| 267 | /// p relative to \c Compare. |
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| 268 | /// \param i The item. |
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| 269 | /// \param p The priority. |
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| 270 | void increase(const Item &i, const Prio &p) { |
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| 271 | int idx = index[i]; |
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| 272 | unlace(idx); |
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| 273 | data[idx].value = p; |
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| 274 | lace(idx); |
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| 275 | } |
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| 276 | |
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| 277 | /// \brief Returns if \c item is in, has already been in, or has |
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| 278 | /// never been in the heap. |
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| 279 | /// |
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| 280 | /// This method returns PRE_HEAP if \c item has never been in the |
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| 281 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
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| 282 | /// otherwise. In the latter case it is possible that \c item will |
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| 283 | /// get back to the heap again. |
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| 284 | /// \param i The item. |
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[2547] | 285 | State state(const Item &i) const { |
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[2038] | 286 | int idx = index[i]; |
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| 287 | if (idx >= 0) idx = 0; |
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[2547] | 288 | return State(idx); |
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[2038] | 289 | } |
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| 290 | |
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| 291 | /// \brief Sets the state of the \c item in the heap. |
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| 292 | /// |
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| 293 | /// Sets the state of the \c item in the heap. It can be used to |
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| 294 | /// manually clear the heap when it is important to achive the |
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| 295 | /// better time complexity. |
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| 296 | /// \param i The item. |
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| 297 | /// \param st The state. It should not be \c IN_HEAP. |
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[2547] | 298 | void state(const Item& i, State st) { |
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[2038] | 299 | switch (st) { |
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| 300 | case POST_HEAP: |
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| 301 | case PRE_HEAP: |
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| 302 | if (state(i) == IN_HEAP) { |
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| 303 | erase(i); |
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| 304 | } |
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| 305 | index[i] = st; |
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| 306 | break; |
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| 307 | case IN_HEAP: |
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| 308 | break; |
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| 309 | } |
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| 310 | } |
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| 311 | |
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| 312 | private: |
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| 313 | |
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| 314 | struct BucketItem { |
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| 315 | BucketItem(const Item& _item, int _value) |
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| 316 | : item(_item), value(_value) {} |
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| 317 | |
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| 318 | Item item; |
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| 319 | int value; |
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| 320 | |
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| 321 | int prev, next; |
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| 322 | }; |
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| 323 | |
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| 324 | ItemIntMap& index; |
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| 325 | std::vector<int> first; |
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| 326 | std::vector<BucketItem> data; |
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| 327 | mutable int minimal; |
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| 328 | |
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| 329 | }; // class BucketHeap |
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| 330 | |
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| 331 | |
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[2263] | 332 | template <typename _ItemIntMap> |
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| 333 | class BucketHeap<_ItemIntMap, false> { |
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[2038] | 334 | |
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| 335 | public: |
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[2263] | 336 | typedef typename _ItemIntMap::Key Item; |
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[2038] | 337 | typedef int Prio; |
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| 338 | typedef std::pair<Item, Prio> Pair; |
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| 339 | typedef _ItemIntMap ItemIntMap; |
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| 340 | |
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[2547] | 341 | enum State { |
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[2038] | 342 | IN_HEAP = 0, |
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| 343 | PRE_HEAP = -1, |
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| 344 | POST_HEAP = -2 |
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| 345 | }; |
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| 346 | |
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| 347 | public: |
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| 348 | |
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| 349 | explicit BucketHeap(ItemIntMap &_index) : index(_index), maximal(-1) {} |
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| 350 | |
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| 351 | int size() const { return data.size(); } |
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| 352 | bool empty() const { return data.empty(); } |
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| 353 | |
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| 354 | void clear() { |
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| 355 | data.clear(); first.clear(); maximal = -1; |
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| 356 | } |
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| 357 | |
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| 358 | private: |
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| 359 | |
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| 360 | void relocate_last(int idx) { |
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[2386] | 361 | if (idx + 1 != int(data.size())) { |
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[2038] | 362 | data[idx] = data.back(); |
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| 363 | if (data[idx].prev != -1) { |
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| 364 | data[data[idx].prev].next = idx; |
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| 365 | } else { |
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| 366 | first[data[idx].value] = idx; |
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| 367 | } |
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| 368 | if (data[idx].next != -1) { |
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| 369 | data[data[idx].next].prev = idx; |
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| 370 | } |
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| 371 | index[data[idx].item] = idx; |
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| 372 | } |
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| 373 | data.pop_back(); |
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| 374 | } |
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| 375 | |
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| 376 | void unlace(int idx) { |
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| 377 | if (data[idx].prev != -1) { |
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| 378 | data[data[idx].prev].next = data[idx].next; |
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| 379 | } else { |
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| 380 | first[data[idx].value] = data[idx].next; |
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| 381 | } |
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| 382 | if (data[idx].next != -1) { |
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| 383 | data[data[idx].next].prev = data[idx].prev; |
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| 384 | } |
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| 385 | } |
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| 386 | |
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| 387 | void lace(int idx) { |
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[2386] | 388 | if (int(first.size()) <= data[idx].value) { |
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[2038] | 389 | first.resize(data[idx].value + 1, -1); |
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| 390 | } |
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| 391 | data[idx].next = first[data[idx].value]; |
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| 392 | if (data[idx].next != -1) { |
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| 393 | data[data[idx].next].prev = idx; |
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| 394 | } |
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| 395 | first[data[idx].value] = idx; |
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| 396 | data[idx].prev = -1; |
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| 397 | } |
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| 398 | |
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| 399 | public: |
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| 400 | |
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| 401 | void push(const Pair& p) { |
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| 402 | push(p.first, p.second); |
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| 403 | } |
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| 404 | |
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| 405 | void push(const Item &i, const Prio &p) { |
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| 406 | int idx = data.size(); |
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| 407 | index[i] = idx; |
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| 408 | data.push_back(BucketItem(i, p)); |
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| 409 | lace(idx); |
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| 410 | if (data[idx].value > maximal) { |
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| 411 | maximal = data[idx].value; |
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| 412 | } |
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| 413 | } |
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| 414 | |
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| 415 | Item top() const { |
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| 416 | while (first[maximal] == -1) { |
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| 417 | --maximal; |
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| 418 | } |
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| 419 | return data[first[maximal]].item; |
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| 420 | } |
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| 421 | |
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| 422 | Prio prio() const { |
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| 423 | while (first[maximal] == -1) { |
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| 424 | --maximal; |
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| 425 | } |
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| 426 | return maximal; |
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| 427 | } |
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| 428 | |
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| 429 | void pop() { |
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| 430 | while (first[maximal] == -1) { |
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| 431 | --maximal; |
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| 432 | } |
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| 433 | int idx = first[maximal]; |
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| 434 | index[data[idx].item] = -2; |
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| 435 | unlace(idx); |
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| 436 | relocate_last(idx); |
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| 437 | } |
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| 438 | |
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| 439 | void erase(const Item &i) { |
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| 440 | int idx = index[i]; |
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| 441 | index[data[idx].item] = -2; |
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| 442 | unlace(idx); |
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| 443 | relocate_last(idx); |
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| 444 | } |
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| 445 | |
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| 446 | Prio operator[](const Item &i) const { |
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| 447 | int idx = index[i]; |
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| 448 | return data[idx].value; |
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| 449 | } |
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| 450 | |
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| 451 | void set(const Item &i, const Prio &p) { |
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| 452 | int idx = index[i]; |
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| 453 | if (idx < 0) { |
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| 454 | push(i,p); |
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| 455 | } else if (p > data[idx].value) { |
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| 456 | decrease(i, p); |
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| 457 | } else { |
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| 458 | increase(i, p); |
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| 459 | } |
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| 460 | } |
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| 461 | |
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| 462 | void decrease(const Item &i, const Prio &p) { |
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| 463 | int idx = index[i]; |
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| 464 | unlace(idx); |
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| 465 | data[idx].value = p; |
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| 466 | if (p > maximal) { |
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| 467 | maximal = p; |
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| 468 | } |
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| 469 | lace(idx); |
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| 470 | } |
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| 471 | |
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| 472 | void increase(const Item &i, const Prio &p) { |
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| 473 | int idx = index[i]; |
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| 474 | unlace(idx); |
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| 475 | data[idx].value = p; |
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| 476 | lace(idx); |
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| 477 | } |
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| 478 | |
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[2547] | 479 | State state(const Item &i) const { |
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[2038] | 480 | int idx = index[i]; |
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| 481 | if (idx >= 0) idx = 0; |
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[2547] | 482 | return State(idx); |
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[2038] | 483 | } |
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| 484 | |
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[2547] | 485 | void state(const Item& i, State st) { |
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[2038] | 486 | switch (st) { |
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| 487 | case POST_HEAP: |
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| 488 | case PRE_HEAP: |
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| 489 | if (state(i) == IN_HEAP) { |
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| 490 | erase(i); |
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| 491 | } |
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| 492 | index[i] = st; |
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| 493 | break; |
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| 494 | case IN_HEAP: |
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| 495 | break; |
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| 496 | } |
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| 497 | } |
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| 498 | |
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| 499 | private: |
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| 500 | |
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| 501 | struct BucketItem { |
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| 502 | BucketItem(const Item& _item, int _value) |
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| 503 | : item(_item), value(_value) {} |
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| 504 | |
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| 505 | Item item; |
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| 506 | int value; |
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| 507 | |
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| 508 | int prev, next; |
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| 509 | }; |
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| 510 | |
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| 511 | ItemIntMap& index; |
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| 512 | std::vector<int> first; |
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| 513 | std::vector<BucketItem> data; |
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| 514 | mutable int maximal; |
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| 515 | |
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| 516 | }; // class BucketHeap |
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| 517 | |
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[2089] | 518 | /// \ingroup auxdat |
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| 519 | /// |
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| 520 | /// \brief A Simplified Bucket Heap implementation. |
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| 521 | /// |
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| 522 | /// This class implements a simplified \e bucket \e heap data |
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| 523 | /// structure. It does not provide some functionality but it faster |
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| 524 | /// and simplier data structure than the BucketHeap. The main |
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| 525 | /// difference is that the BucketHeap stores for every key a double |
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| 526 | /// linked list while this class stores just simple lists. In the |
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| 527 | /// other way it does not supports erasing each elements just the |
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| 528 | /// minimal and it does not supports key increasing, decreasing. |
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| 529 | /// |
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| 530 | /// \param _ItemIntMap A read and writable Item int map, used internally |
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| 531 | /// to handle the cross references. |
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| 532 | /// \param minimize If the given parameter is true then the heap gives back |
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| 533 | /// the lowest priority. |
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| 534 | /// |
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| 535 | /// \sa BucketHeap |
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[2263] | 536 | template <typename _ItemIntMap, bool minimize = true > |
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[2089] | 537 | class SimpleBucketHeap { |
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| 538 | |
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| 539 | public: |
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[2263] | 540 | typedef typename _ItemIntMap::Key Item; |
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[2089] | 541 | typedef int Prio; |
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| 542 | typedef std::pair<Item, Prio> Pair; |
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| 543 | typedef _ItemIntMap ItemIntMap; |
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| 544 | |
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| 545 | /// \brief Type to represent the items states. |
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| 546 | /// |
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| 547 | /// Each Item element have a state associated to it. It may be "in heap", |
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| 548 | /// "pre heap" or "post heap". The latter two are indifferent from the |
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| 549 | /// heap's point of view, but may be useful to the user. |
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| 550 | /// |
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| 551 | /// The ItemIntMap \e should be initialized in such way that it maps |
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| 552 | /// PRE_HEAP (-1) to any element to be put in the heap... |
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[2547] | 553 | enum State { |
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[2089] | 554 | IN_HEAP = 0, |
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| 555 | PRE_HEAP = -1, |
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| 556 | POST_HEAP = -2 |
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| 557 | }; |
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| 558 | |
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| 559 | public: |
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| 560 | |
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| 561 | /// \brief The constructor. |
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| 562 | /// |
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| 563 | /// The constructor. |
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| 564 | /// \param _index should be given to the constructor, since it is used |
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| 565 | /// internally to handle the cross references. The value of the map |
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| 566 | /// should be PRE_HEAP (-1) for each element. |
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| 567 | explicit SimpleBucketHeap(ItemIntMap &_index) |
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| 568 | : index(_index), free(-1), num(0), minimal(0) {} |
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| 569 | |
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| 570 | /// \brief Returns the number of items stored in the heap. |
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| 571 | /// |
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| 572 | /// The number of items stored in the heap. |
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| 573 | int size() const { return num; } |
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| 574 | |
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| 575 | /// \brief Checks if the heap stores no items. |
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| 576 | /// |
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| 577 | /// Returns \c true if and only if the heap stores no items. |
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| 578 | bool empty() const { return num == 0; } |
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| 579 | |
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| 580 | /// \brief Make empty this heap. |
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| 581 | /// |
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| 582 | /// Make empty this heap. It does not change the cross reference |
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| 583 | /// map. If you want to reuse a heap what is not surely empty you |
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| 584 | /// should first clear the heap and after that you should set the |
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| 585 | /// cross reference map for each item to \c PRE_HEAP. |
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| 586 | void clear() { |
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| 587 | data.clear(); first.clear(); free = -1; num = 0; minimal = 0; |
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| 588 | } |
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| 589 | |
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| 590 | /// \brief Insert a pair of item and priority into the heap. |
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| 591 | /// |
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| 592 | /// Adds \c p.first to the heap with priority \c p.second. |
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| 593 | /// \param p The pair to insert. |
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| 594 | void push(const Pair& p) { |
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| 595 | push(p.first, p.second); |
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| 596 | } |
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| 597 | |
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| 598 | /// \brief Insert an item into the heap with the given priority. |
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| 599 | /// |
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| 600 | /// Adds \c i to the heap with priority \c p. |
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| 601 | /// \param i The item to insert. |
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| 602 | /// \param p The priority of the item. |
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| 603 | void push(const Item &i, const Prio &p) { |
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| 604 | int idx; |
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| 605 | if (free == -1) { |
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| 606 | idx = data.size(); |
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[2110] | 607 | data.push_back(BucketItem(i)); |
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[2089] | 608 | } else { |
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| 609 | idx = free; |
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| 610 | free = data[idx].next; |
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[2110] | 611 | data[idx].item = i; |
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[2089] | 612 | } |
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| 613 | index[i] = idx; |
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[2386] | 614 | if (p >= int(first.size())) first.resize(p + 1, -1); |
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[2089] | 615 | data[idx].next = first[p]; |
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| 616 | first[p] = idx; |
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| 617 | if (p < minimal) { |
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| 618 | minimal = p; |
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| 619 | } |
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| 620 | ++num; |
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| 621 | } |
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| 622 | |
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| 623 | /// \brief Returns the item with minimum priority. |
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| 624 | /// |
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| 625 | /// This method returns the item with minimum priority. |
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| 626 | /// \pre The heap must be nonempty. |
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| 627 | Item top() const { |
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| 628 | while (first[minimal] == -1) { |
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| 629 | ++minimal; |
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| 630 | } |
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| 631 | return data[first[minimal]].item; |
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| 632 | } |
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| 633 | |
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| 634 | /// \brief Returns the minimum priority. |
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| 635 | /// |
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| 636 | /// It returns the minimum priority. |
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| 637 | /// \pre The heap must be nonempty. |
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| 638 | Prio prio() const { |
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| 639 | while (first[minimal] == -1) { |
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| 640 | ++minimal; |
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| 641 | } |
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| 642 | return minimal; |
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| 643 | } |
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| 644 | |
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| 645 | /// \brief Deletes the item with minimum priority. |
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| 646 | /// |
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| 647 | /// This method deletes the item with minimum priority from the heap. |
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| 648 | /// \pre The heap must be non-empty. |
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| 649 | void pop() { |
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| 650 | while (first[minimal] == -1) { |
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| 651 | ++minimal; |
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| 652 | } |
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| 653 | int idx = first[minimal]; |
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| 654 | index[data[idx].item] = -2; |
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| 655 | first[minimal] = data[idx].next; |
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| 656 | data[idx].next = free; |
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| 657 | free = idx; |
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| 658 | --num; |
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| 659 | } |
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| 660 | |
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| 661 | /// \brief Returns the priority of \c i. |
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| 662 | /// |
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[2110] | 663 | /// This function returns the priority of item \c i. |
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| 664 | /// \warning This operator is not a constant time function |
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| 665 | /// because it scans the whole data structure to find the proper |
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| 666 | /// value. |
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[2089] | 667 | /// \pre \c i must be in the heap. |
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| 668 | /// \param i The item. |
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| 669 | Prio operator[](const Item &i) const { |
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[2110] | 670 | for (int k = 0; k < first.size(); ++k) { |
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| 671 | int idx = first[k]; |
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| 672 | while (idx != -1) { |
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| 673 | if (data[idx].item == i) { |
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| 674 | return k; |
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| 675 | } |
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| 676 | idx = data[idx].next; |
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| 677 | } |
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| 678 | } |
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| 679 | return -1; |
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[2089] | 680 | } |
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| 681 | |
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| 682 | /// \brief Returns if \c item is in, has already been in, or has |
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| 683 | /// never been in the heap. |
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| 684 | /// |
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| 685 | /// This method returns PRE_HEAP if \c item has never been in the |
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| 686 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
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| 687 | /// otherwise. In the latter case it is possible that \c item will |
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| 688 | /// get back to the heap again. |
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| 689 | /// \param i The item. |
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[2547] | 690 | State state(const Item &i) const { |
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[2089] | 691 | int idx = index[i]; |
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| 692 | if (idx >= 0) idx = 0; |
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[2547] | 693 | return State(idx); |
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[2089] | 694 | } |
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| 695 | |
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| 696 | private: |
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| 697 | |
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| 698 | struct BucketItem { |
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[2110] | 699 | BucketItem(const Item& _item) |
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| 700 | : item(_item) {} |
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[2089] | 701 | |
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| 702 | Item item; |
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| 703 | int next; |
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| 704 | }; |
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| 705 | |
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| 706 | ItemIntMap& index; |
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| 707 | std::vector<int> first; |
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| 708 | std::vector<BucketItem> data; |
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| 709 | int free, num; |
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| 710 | mutable int minimal; |
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| 711 | |
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| 712 | }; // class SimpleBucketHeap |
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| 713 | |
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[2263] | 714 | template <typename _ItemIntMap> |
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| 715 | class SimpleBucketHeap<_ItemIntMap, false> { |
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[2089] | 716 | |
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| 717 | public: |
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[2263] | 718 | typedef typename _ItemIntMap::Key Item; |
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[2089] | 719 | typedef int Prio; |
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| 720 | typedef std::pair<Item, Prio> Pair; |
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| 721 | typedef _ItemIntMap ItemIntMap; |
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| 722 | |
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[2547] | 723 | enum State { |
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[2089] | 724 | IN_HEAP = 0, |
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| 725 | PRE_HEAP = -1, |
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| 726 | POST_HEAP = -2 |
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| 727 | }; |
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| 728 | |
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| 729 | public: |
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| 730 | |
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| 731 | explicit SimpleBucketHeap(ItemIntMap &_index) |
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| 732 | : index(_index), free(-1), num(0), maximal(0) {} |
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| 733 | |
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| 734 | int size() const { return num; } |
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| 735 | |
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| 736 | bool empty() const { return num == 0; } |
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| 737 | |
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| 738 | void clear() { |
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| 739 | data.clear(); first.clear(); free = -1; num = 0; maximal = 0; |
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| 740 | } |
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| 741 | |
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| 742 | void push(const Pair& p) { |
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| 743 | push(p.first, p.second); |
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| 744 | } |
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| 745 | |
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| 746 | void push(const Item &i, const Prio &p) { |
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| 747 | int idx; |
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| 748 | if (free == -1) { |
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| 749 | idx = data.size(); |
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[2110] | 750 | data.push_back(BucketItem(i)); |
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[2089] | 751 | } else { |
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| 752 | idx = free; |
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| 753 | free = data[idx].next; |
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[2110] | 754 | data[idx].item = i; |
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[2089] | 755 | } |
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| 756 | index[i] = idx; |
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[2386] | 757 | if (p >= int(first.size())) first.resize(p + 1, -1); |
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[2089] | 758 | data[idx].next = first[p]; |
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| 759 | first[p] = idx; |
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| 760 | if (p > maximal) { |
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| 761 | maximal = p; |
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| 762 | } |
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| 763 | ++num; |
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| 764 | } |
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| 765 | |
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| 766 | Item top() const { |
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| 767 | while (first[maximal] == -1) { |
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| 768 | --maximal; |
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| 769 | } |
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| 770 | return data[first[maximal]].item; |
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| 771 | } |
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| 772 | |
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| 773 | Prio prio() const { |
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| 774 | while (first[maximal] == -1) { |
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| 775 | --maximal; |
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| 776 | } |
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| 777 | return maximal; |
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| 778 | } |
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| 779 | |
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| 780 | void pop() { |
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| 781 | while (first[maximal] == -1) { |
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| 782 | --maximal; |
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| 783 | } |
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| 784 | int idx = first[maximal]; |
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| 785 | index[data[idx].item] = -2; |
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| 786 | first[maximal] = data[idx].next; |
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| 787 | data[idx].next = free; |
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| 788 | free = idx; |
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| 789 | --num; |
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| 790 | } |
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| 791 | |
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| 792 | Prio operator[](const Item &i) const { |
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[2110] | 793 | for (int k = 0; k < first.size(); ++k) { |
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| 794 | int idx = first[k]; |
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| 795 | while (idx != -1) { |
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| 796 | if (data[idx].item == i) { |
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| 797 | return k; |
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| 798 | } |
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| 799 | idx = data[idx].next; |
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| 800 | } |
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| 801 | } |
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| 802 | return -1; |
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[2089] | 803 | } |
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| 804 | |
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[2547] | 805 | State state(const Item &i) const { |
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[2089] | 806 | int idx = index[i]; |
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| 807 | if (idx >= 0) idx = 0; |
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[2547] | 808 | return State(idx); |
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[2089] | 809 | } |
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| 810 | |
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| 811 | private: |
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| 812 | |
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| 813 | struct BucketItem { |
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[2110] | 814 | BucketItem(const Item& _item) : item(_item) {} |
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[2089] | 815 | |
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| 816 | Item item; |
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| 817 | |
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| 818 | int next; |
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| 819 | }; |
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| 820 | |
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| 821 | ItemIntMap& index; |
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| 822 | std::vector<int> first; |
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| 823 | std::vector<BucketItem> data; |
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| 824 | int free, num; |
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| 825 | mutable int maximal; |
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| 826 | |
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| 827 | }; |
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| 828 | |
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[2038] | 829 | } |
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| 830 | |
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| 831 | #endif |
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