| 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
| 2 | * |
| 3 | * This file is a part of LEMON, a generic C++ optimization library. |
| 4 | * |
| 5 | * Copyright (C) 2003-2008 |
| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
| 8 | * |
| 9 | * Permission to use, modify and distribute this software is granted |
| 10 | * provided that this copyright notice appears in all copies. For |
| 11 | * precise terms see the accompanying LICENSE file. |
| 12 | * |
| 13 | * This software is provided "AS IS" with no warranty of any kind, |
| 14 | * express or implied, and with no claim as to its suitability for any |
| 15 | * purpose. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | #ifndef LEMON_BITS_SOLVER_BITS_H |
| 20 | #define LEMON_BITS_SOLVER_BITS_H |
| 21 | |
| 22 | namespace lemon { |
| 23 | |
| 24 | namespace _solver_bits { |
| 25 | |
| 26 | class VarIndex { |
| 27 | private: |
| 28 | struct ItemT { |
| 29 | int prev, next; |
| 30 | int index; |
| 31 | }; |
| 32 | std::vector<ItemT> items; |
| 33 | int first_item, last_item, first_free_item; |
| 34 | |
| 35 | std::vector<int> cross; |
| 36 | |
| 37 | public: |
| 38 | |
| 39 | VarIndex() |
| 40 | : first_item(-1), last_item(-1), first_free_item(-1) { |
| 41 | } |
| 42 | |
| 43 | void clear() { |
| 44 | first_item = -1; |
| 45 | first_free_item = -1; |
| 46 | items.clear(); |
| 47 | cross.clear(); |
| 48 | } |
| 49 | |
| 50 | int addIndex(int idx) { |
| 51 | int n; |
| 52 | if (first_free_item == -1) { |
| 53 | n = items.size(); |
| 54 | items.push_back(ItemT()); |
| 55 | } else { |
| 56 | n = first_free_item; |
| 57 | first_free_item = items[n].next; |
| 58 | if (first_free_item != -1) { |
| 59 | items[first_free_item].prev = -1; |
| 60 | } |
| 61 | } |
| 62 | items[n].index = idx; |
| 63 | if (static_cast<int>(cross.size()) <= idx) { |
| 64 | cross.resize(idx + 1, -1); |
| 65 | } |
| 66 | cross[idx] = n; |
| 67 | |
| 68 | items[n].prev = last_item; |
| 69 | items[n].next = -1; |
| 70 | if (last_item != -1) { |
| 71 | items[last_item].next = n; |
| 72 | } else { |
| 73 | first_item = n; |
| 74 | } |
| 75 | last_item = n; |
| 76 | |
| 77 | return n; |
| 78 | } |
| 79 | |
| 80 | int addIndex(int idx, int n) { |
| 81 | while (n >= static_cast<int>(items.size())) { |
| 82 | items.push_back(ItemT()); |
| 83 | items.back().prev = -1; |
| 84 | items.back().next = first_free_item; |
| 85 | if (first_free_item != -1) { |
| 86 | items[first_free_item].prev = items.size() - 1; |
| 87 | } |
| 88 | first_free_item = items.size() - 1; |
| 89 | } |
| 90 | if (items[n].next != -1) { |
| 91 | items[items[n].next].prev = items[n].prev; |
| 92 | } |
| 93 | if (items[n].prev != -1) { |
| 94 | items[items[n].prev].next = items[n].next; |
| 95 | } else { |
| 96 | first_free_item = items[n].next; |
| 97 | } |
| 98 | |
| 99 | items[n].index = idx; |
| 100 | if (static_cast<int>(cross.size()) <= idx) { |
| 101 | cross.resize(idx + 1, -1); |
| 102 | } |
| 103 | cross[idx] = n; |
| 104 | |
| 105 | items[n].prev = last_item; |
| 106 | items[n].next = -1; |
| 107 | if (last_item != -1) { |
| 108 | items[last_item].next = n; |
| 109 | } else { |
| 110 | first_item = n; |
| 111 | } |
| 112 | last_item = n; |
| 113 | |
| 114 | return n; |
| 115 | } |
| 116 | |
| 117 | void eraseIndex(int idx) { |
| 118 | int n = cross[idx]; |
| 119 | |
| 120 | if (items[n].prev != -1) { |
| 121 | items[items[n].prev].next = items[n].next; |
| 122 | } else { |
| 123 | first_item = items[n].next; |
| 124 | } |
| 125 | if (items[n].next != -1) { |
| 126 | items[items[n].next].prev = items[n].prev; |
| 127 | } else { |
| 128 | last_item = items[n].prev; |
| 129 | } |
| 130 | |
| 131 | if (first_free_item != -1) { |
| 132 | items[first_free_item].prev = n; |
| 133 | } |
| 134 | items[n].next = first_free_item; |
| 135 | items[n].prev = -1; |
| 136 | first_free_item = n; |
| 137 | |
| 138 | while (!cross.empty() && cross.back() == -1) { |
| 139 | cross.pop_back(); |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | int maxIndex() const { |
| 144 | return cross.size() - 1; |
| 145 | } |
| 146 | |
| 147 | void shiftIndices(int idx) { |
| 148 | for (int i = idx + 1; i < static_cast<int>(cross.size()); ++i) { |
| 149 | cross[i - 1] = cross[i]; |
| 150 | if (cross[i] != -1) { |
| 151 | --items[cross[i]].index; |
| 152 | } |
| 153 | } |
| 154 | cross.back() = -1; |
| 155 | cross.pop_back(); |
| 156 | while (!cross.empty() && cross.back() == -1) { |
| 157 | cross.pop_back(); |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | void relocateIndex(int idx, int jdx) { |
| 162 | cross[idx] = cross[jdx]; |
| 163 | items[cross[jdx]].index = idx; |
| 164 | cross[jdx] = -1; |
| 165 | |
| 166 | while (!cross.empty() && cross.back() == -1) { |
| 167 | cross.pop_back(); |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | int operator[](int idx) const { |
| 172 | return cross[idx]; |
| 173 | } |
| 174 | |
| 175 | int operator()(int fdx) const { |
| 176 | return items[fdx].index; |
| 177 | } |
| 178 | |
| 179 | void firstItem(int& fdx) const { |
| 180 | fdx = first_item; |
| 181 | } |
| 182 | |
| 183 | void nextItem(int& fdx) const { |
| 184 | fdx = items[fdx].next; |
| 185 | } |
| 186 | |
| 187 | }; |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | #endif |