[1186] | 1 | /* -*- C++ -*- |
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| 2 | * src/lemon/bin_heap.h - Part of LEMON, a generic C++ optimization library |
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| 3 | * |
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| 4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 5 | * (Egervary Combinatorial Optimization Research Group, EGRES). |
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| 6 | * |
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| 7 | * Permission to use, modify and distribute this software is granted |
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| 8 | * provided that this copyright notice appears in all copies. For |
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| 9 | * precise terms see the accompanying LICENSE file. |
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| 10 | * |
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| 11 | * This software is provided "AS IS" with no warranty of any kind, |
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| 12 | * express or implied, and with no claim as to its suitability for any |
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| 13 | * purpose. |
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| 14 | * |
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| 15 | */ |
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| 16 | |
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| 17 | #ifndef LEMON_RADIX_HEAP_H |
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| 18 | #define LEMON_RADIX_HEAP_H |
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| 19 | |
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| 20 | ///\ingroup auxdat |
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| 21 | ///\file |
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| 22 | ///\brief Radix Heap implementation. |
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| 23 | ///\todo It should be documented. |
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| 24 | |
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| 25 | #include <vector> |
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| 26 | #include <lemon/error.h> |
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| 27 | |
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| 28 | namespace lemon { |
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| 29 | |
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| 30 | /// \addtogroup auxdat |
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| 31 | /// @{ |
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| 32 | |
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[1205] | 33 | /// A Radix Heap implementation. |
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[1186] | 34 | |
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| 35 | ///\todo Please document... |
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| 36 | /// |
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| 37 | ///\sa BinHeap |
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| 38 | ///\sa Dijkstra |
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| 39 | |
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| 40 | class UnderFlowPriorityException : public RuntimeError { |
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| 41 | public: |
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| 42 | virtual const char* exceptionName() const { |
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| 43 | return "lemon::UnderFlowPriorityException"; |
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| 44 | } |
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| 45 | }; |
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| 46 | |
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| 47 | template <typename _Item, typename _ItemIntMap> |
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| 48 | class RadixHeap { |
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| 49 | |
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| 50 | public: |
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| 51 | typedef _Item Item; |
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| 52 | // FIXME: stl-ben nem ezt hivjak value_type -nak, hanem a kovetkezot... |
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| 53 | typedef int Prio; |
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| 54 | typedef _ItemIntMap ItemIntMap; |
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| 55 | |
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| 56 | /** |
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| 57 | * Each Item element have a state associated to it. It may be "in heap", |
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| 58 | * "pre heap" or "post heap". The later two are indifferent from the |
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| 59 | * heap's point of view, but may be useful to the user. |
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| 60 | * |
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| 61 | * The ItemIntMap _should_ be initialized in such way, that it maps |
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| 62 | * PRE_HEAP (-1) to any element to be put in the heap... |
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| 63 | */ |
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| 64 | ///\todo it is used nowhere |
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| 65 | /// |
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| 66 | enum state_enum { |
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| 67 | IN_HEAP = 0, |
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| 68 | PRE_HEAP = -1, |
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| 69 | POST_HEAP = -2 |
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| 70 | }; |
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| 71 | |
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| 72 | private: |
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| 73 | |
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| 74 | struct RadixItem { |
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| 75 | int prev, next, box; |
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| 76 | Item item; |
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| 77 | int prio; |
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| 78 | RadixItem(Item _item, int _prio) : item(_item), prio(_prio) {} |
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| 79 | }; |
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| 80 | |
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| 81 | struct RadixBox { |
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| 82 | int first; |
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| 83 | int min, size; |
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| 84 | RadixBox(int _min, int _size) : first(-1), min(_min), size(_size) {} |
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| 85 | }; |
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| 86 | |
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| 87 | std::vector<RadixItem> data; |
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| 88 | std::vector<RadixBox> boxes; |
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| 89 | |
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| 90 | ItemIntMap &iim; |
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| 91 | |
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| 92 | |
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| 93 | public: |
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| 94 | ///\e |
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| 95 | explicit RadixHeap(ItemIntMap &_iim) : iim(_iim) { |
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| 96 | boxes.push_back(RadixBox(0, 1)); |
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| 97 | boxes.push_back(RadixBox(1, 1)); |
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| 98 | } |
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| 99 | |
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| 100 | ///\e |
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| 101 | RadixHeap(ItemIntMap &_iim, int capacity) : iim(_iim) { |
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| 102 | boxes.push_back(RadixBox(0, 1)); |
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| 103 | boxes.push_back(RadixBox(1, 1)); |
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| 104 | while (upper(boxes.back(), capacity)) { |
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| 105 | extend(); |
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| 106 | } |
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| 107 | } |
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| 108 | |
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| 109 | ///\e |
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| 110 | int size() const { return data.size(); } |
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| 111 | ///\e |
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| 112 | bool empty() const { return data.empty(); } |
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| 113 | |
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| 114 | private: |
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| 115 | |
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| 116 | bool upper(int box, Prio prio) { |
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| 117 | return prio < boxes[box].min; |
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| 118 | } |
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| 119 | |
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| 120 | bool lower(int box, Prio prio) { |
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| 121 | return prio >= boxes[box].min + boxes[box].size; |
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| 122 | } |
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| 123 | |
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| 124 | /// \brief Remove item from the box list. |
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| 125 | void remove(int index) { |
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| 126 | if (data[index].prev >= 0) { |
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| 127 | data[data[index].prev].next = data[index].next; |
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| 128 | } else { |
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| 129 | boxes[data[index].box].first = data[index].next; |
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| 130 | } |
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| 131 | if (data[index].next >= 0) { |
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| 132 | data[data[index].next].prev = data[index].prev; |
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| 133 | } |
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| 134 | } |
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| 135 | |
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| 136 | /// \brief Insert item into the box list. |
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| 137 | void insert(int box, int index) { |
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| 138 | if (boxes[box].first == -1) { |
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| 139 | boxes[box].first = index; |
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| 140 | data[index].next = data[index].prev = -1; |
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| 141 | } else { |
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| 142 | data[index].next = boxes[box].first; |
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| 143 | data[boxes[box].first].prev = index; |
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| 144 | data[index].prev = -1; |
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| 145 | boxes[box].first = index; |
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| 146 | } |
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| 147 | data[index].box = box; |
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| 148 | } |
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| 149 | |
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| 150 | /// \brief Add a new box to the box list. |
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| 151 | void extend() { |
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| 152 | int min = boxes.back().min + boxes.back().size; |
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| 153 | int size = 2 * boxes.back().size; |
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| 154 | boxes.push_back(RadixBox(min, size)); |
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| 155 | } |
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| 156 | |
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| 157 | /// \brief Move an item up into the proper box. |
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| 158 | void bubble_up(int index) { |
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[1205] | 159 | if (!lower(data[index].box, data[index].prio)) return; |
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[1186] | 160 | remove(index); |
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| 161 | int box = findUp(data[index].box, data[index].prio); |
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| 162 | insert(box, index); |
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| 163 | } |
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| 164 | |
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| 165 | /// \brief Find up the proper box for the item with the given prio. |
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| 166 | int findUp(int start, int prio) { |
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| 167 | while (lower(start, prio)) { |
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| 168 | if (++start == (int)boxes.size()) { |
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| 169 | extend(); |
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| 170 | } |
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| 171 | } |
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| 172 | return start; |
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| 173 | } |
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| 174 | |
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| 175 | /// \brief Move an item down into the proper box. |
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| 176 | void bubble_down(int index) { |
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| 177 | if (!upper(data[index].box, data[index].prio)) return; |
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| 178 | remove(index); |
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| 179 | int box = findDown(data[index].box, data[index].prio); |
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| 180 | insert(box, index); |
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| 181 | } |
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| 182 | |
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| 183 | /// \brief Find up the proper box for the item with the given prio. |
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| 184 | int findDown(int start, int prio) { |
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| 185 | while (upper(start, prio)) { |
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| 186 | if (--start < 0) throw UnderFlowPriorityException(); |
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| 187 | } |
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| 188 | return start; |
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| 189 | } |
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| 190 | |
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| 191 | /// \brief Find the first not empty box. |
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| 192 | int findFirst() { |
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| 193 | int first = 0; |
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| 194 | while (boxes[first].first == -1) ++first; |
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| 195 | return first; |
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| 196 | } |
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| 197 | |
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| 198 | /// \brief Gives back the minimal prio of the box. |
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| 199 | int minValue(int box) { |
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| 200 | int min = data[boxes[box].first].prio; |
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| 201 | for (int k = boxes[box].first; k != -1; k = data[k].next) { |
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| 202 | if (data[k].prio < min) min = data[k].prio; |
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| 203 | } |
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| 204 | return min; |
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| 205 | } |
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| 206 | |
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| 207 | /// \brief Rearrange the items of the heap and makes the |
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| 208 | /// first box not empty. |
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| 209 | void moveDown() { |
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| 210 | // print(); printf("moveDown\n"); fflush(stdout); |
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| 211 | int box = findFirst(); |
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| 212 | if (box == 0) return; |
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| 213 | int min = minValue(box); |
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| 214 | for (int i = 0; i <= box; ++i) { |
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| 215 | boxes[i].min = min; |
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| 216 | min += boxes[i].size; |
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| 217 | } |
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| 218 | int curr = boxes[box].first, next; |
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| 219 | while (curr != -1) { |
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| 220 | next = data[curr].next; |
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| 221 | bubble_down(curr); |
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| 222 | curr = next; |
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| 223 | } |
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| 224 | } |
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| 225 | |
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| 226 | void relocate_last(int index) { |
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| 227 | if (index != (int)data.size() - 1) { |
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| 228 | data[index] = data.back(); |
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| 229 | if (data[index].prev != -1) { |
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| 230 | data[data[index].prev].next = index; |
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| 231 | } else { |
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| 232 | boxes[data[index].box].first = index; |
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| 233 | } |
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| 234 | if (data[index].next != -1) { |
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| 235 | data[data[index].next].prev = index; |
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| 236 | } |
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| 237 | iim[data[index].item] = index; |
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| 238 | } |
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| 239 | data.pop_back(); |
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| 240 | } |
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| 241 | |
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| 242 | public: |
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| 243 | |
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| 244 | ///\e |
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| 245 | void push(const Item &i, const Prio &p) { |
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| 246 | fflush(stdout); |
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| 247 | int n = data.size(); |
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| 248 | iim.set(i, n); |
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| 249 | data.push_back(RadixItem(i, p)); |
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| 250 | while (lower(boxes.size() - 1, p)) { |
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| 251 | extend(); |
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| 252 | } |
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| 253 | int box = findDown(boxes.size() - 1, p); |
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| 254 | insert(box, n); |
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| 255 | // printf("Push %d\n", p); |
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| 256 | //print(); |
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| 257 | } |
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| 258 | |
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| 259 | ///\e |
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| 260 | Item top() const { |
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| 261 | // print(); printf("top\n"); fflush(stdout); |
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| 262 | const_cast<RadixHeap<Item, ItemIntMap>*>(this)->moveDown(); |
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| 263 | return data[boxes[0].first].item; |
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| 264 | // print(); printf("top_end\n"); fflush(stdout); |
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| 265 | } |
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| 266 | |
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| 267 | /// Returns the prio of the top element of the heap. |
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| 268 | Prio prio() const { |
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| 269 | // print(); printf("prio\n"); fflush(stdout); |
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| 270 | const_cast<RadixHeap<Item, ItemIntMap>*>(this)->moveDown(); |
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| 271 | return data[boxes[0].first].prio; |
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| 272 | } |
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| 273 | |
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| 274 | ///\e |
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| 275 | void pop() { |
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| 276 | // print(); printf("pop\n"); fflush(stdout); |
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| 277 | moveDown(); |
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| 278 | int index = boxes[0].first; |
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| 279 | iim[data[index].item] = POST_HEAP; |
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| 280 | remove(index); |
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| 281 | relocate_last(index); |
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| 282 | // printf("Pop \n"); |
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| 283 | //print(); |
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| 284 | } |
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| 285 | |
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| 286 | ///\e |
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| 287 | void erase(const Item &i) { |
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| 288 | int index = iim[i]; |
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| 289 | iim[i] = POST_HEAP; |
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| 290 | remove(index); |
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| 291 | relocate_last(index); |
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| 292 | } |
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| 293 | |
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| 294 | ///\e |
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| 295 | Prio operator[](const Item &i) const { |
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| 296 | int idx = iim[i]; |
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| 297 | return data[idx].prio; |
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| 298 | } |
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| 299 | |
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| 300 | ///\e |
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| 301 | void set(const Item &i, const Prio &p) { |
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| 302 | int idx = iim[i]; |
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| 303 | if( idx < 0 ) { |
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| 304 | push(i, p); |
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| 305 | } |
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| 306 | else if( p >= data[idx].prio ) { |
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| 307 | data[idx].prio = p; |
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| 308 | bubble_up(idx); |
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| 309 | } else { |
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| 310 | data[idx].prio = p; |
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| 311 | bubble_down(idx); |
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| 312 | } |
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| 313 | } |
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| 314 | |
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| 315 | ///\e |
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| 316 | void decrease(const Item &i, const Prio &p) { |
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| 317 | // print(); printf("decrease\n"); fflush(stdout); |
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| 318 | int idx = iim[i]; |
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| 319 | data[idx].prio = p; |
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| 320 | bubble_down(idx); |
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| 321 | } |
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| 322 | |
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| 323 | ///\e |
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| 324 | void increase(const Item &i, const Prio &p) { |
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| 325 | int idx = iim[i]; |
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| 326 | data[idx].prio = p; |
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| 327 | bubble_up(idx); |
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| 328 | } |
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| 329 | |
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| 330 | ///\e |
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| 331 | state_enum state(const Item &i) const { |
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| 332 | int s = iim[i]; |
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| 333 | if( s >= 0 ) s = 0; |
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| 334 | return state_enum(s); |
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| 335 | } |
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| 336 | |
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[1205] | 337 | // void print() const { |
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| 338 | // for (int i = 0; i < boxes.size(); ++i) { |
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| 339 | // printf("(%d, %d) ", boxes[i].min, boxes[i].size); |
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| 340 | // for (int k = boxes[i].first; k != -1; k = data[k].next) { |
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| 341 | // printf("%d ", data[k].prio); |
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| 342 | // } |
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| 343 | // printf("\n"); |
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| 344 | // } |
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| 345 | // fflush(stdout); |
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| 346 | // } |
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[1186] | 347 | |
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| 348 | }; // class RadixHeap |
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| 349 | |
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| 350 | |
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| 351 | ///@} |
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| 352 | |
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| 353 | } // namespace lemon |
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| 354 | |
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| 355 | #endif // LEMON_RADIX_HEAP_H |
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