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1 /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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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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5 * Copyright (C) 2003-2008 |
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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_BITS_SOLVER_BITS_H |
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20 #define LEMON_BITS_SOLVER_BITS_H |
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21 |
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22 namespace lemon { |
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23 |
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24 namespace _solver_bits { |
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25 |
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26 class VarIndex { |
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27 private: |
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28 struct ItemT { |
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29 int prev, next; |
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30 int index; |
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31 }; |
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32 std::vector<ItemT> items; |
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33 int first_item, last_item, first_free_item; |
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34 |
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35 std::vector<int> cross; |
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36 |
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37 public: |
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38 |
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39 VarIndex() |
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40 : first_item(-1), last_item(-1), first_free_item(-1) { |
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41 } |
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42 |
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43 void clear() { |
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44 first_item = -1; |
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45 first_free_item = -1; |
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46 items.clear(); |
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47 cross.clear(); |
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48 } |
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49 |
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50 int addIndex(int idx) { |
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51 int n; |
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52 if (first_free_item == -1) { |
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53 n = items.size(); |
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54 items.push_back(ItemT()); |
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55 } else { |
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56 n = first_free_item; |
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57 first_free_item = items[n].next; |
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58 if (first_free_item != -1) { |
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59 items[first_free_item].prev = -1; |
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60 } |
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61 } |
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62 items[n].index = idx; |
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63 if (static_cast<int>(cross.size()) <= idx) { |
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64 cross.resize(idx + 1, -1); |
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65 } |
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66 cross[idx] = n; |
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67 |
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68 items[n].prev = last_item; |
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69 items[n].next = -1; |
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70 if (last_item != -1) { |
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71 items[last_item].next = n; |
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72 } else { |
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73 first_item = n; |
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74 } |
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75 last_item = n; |
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76 |
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77 return n; |
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78 } |
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79 |
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80 int addIndex(int idx, int n) { |
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81 while (n >= static_cast<int>(items.size())) { |
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82 items.push_back(ItemT()); |
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83 items.back().prev = -1; |
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84 items.back().next = first_free_item; |
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85 if (first_free_item != -1) { |
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86 items[first_free_item].prev = items.size() - 1; |
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87 } |
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88 first_free_item = items.size() - 1; |
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89 } |
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90 if (items[n].next != -1) { |
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91 items[items[n].next].prev = items[n].prev; |
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92 } |
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93 if (items[n].prev != -1) { |
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94 items[items[n].prev].next = items[n].next; |
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95 } else { |
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96 first_free_item = items[n].next; |
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97 } |
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98 |
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99 items[n].index = idx; |
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100 if (static_cast<int>(cross.size()) <= idx) { |
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101 cross.resize(idx + 1, -1); |
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102 } |
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103 cross[idx] = n; |
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104 |
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105 items[n].prev = last_item; |
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106 items[n].next = -1; |
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107 if (last_item != -1) { |
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108 items[last_item].next = n; |
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109 } else { |
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110 first_item = n; |
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111 } |
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112 last_item = n; |
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113 |
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114 return n; |
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115 } |
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116 |
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117 void eraseIndex(int idx) { |
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118 int n = cross[idx]; |
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119 |
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120 if (items[n].prev != -1) { |
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121 items[items[n].prev].next = items[n].next; |
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122 } else { |
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123 first_item = items[n].next; |
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124 } |
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125 if (items[n].next != -1) { |
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126 items[items[n].next].prev = items[n].prev; |
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127 } else { |
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128 last_item = items[n].prev; |
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129 } |
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130 |
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131 if (first_free_item != -1) { |
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132 items[first_free_item].prev = n; |
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133 } |
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134 items[n].next = first_free_item; |
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135 items[n].prev = -1; |
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136 first_free_item = n; |
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137 |
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138 while (!cross.empty() && cross.back() == -1) { |
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139 cross.pop_back(); |
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140 } |
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141 } |
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142 |
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143 int maxIndex() const { |
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144 return cross.size() - 1; |
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145 } |
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146 |
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147 void shiftIndices(int idx) { |
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148 for (int i = idx + 1; i < static_cast<int>(cross.size()); ++i) { |
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149 cross[i - 1] = cross[i]; |
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150 if (cross[i] != -1) { |
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151 --items[cross[i]].index; |
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152 } |
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153 } |
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154 cross.back() = -1; |
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155 cross.pop_back(); |
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156 while (!cross.empty() && cross.back() == -1) { |
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157 cross.pop_back(); |
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158 } |
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159 } |
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160 |
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161 void relocateIndex(int idx, int jdx) { |
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162 cross[idx] = cross[jdx]; |
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163 items[cross[jdx]].index = idx; |
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164 cross[jdx] = -1; |
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165 |
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166 while (!cross.empty() && cross.back() == -1) { |
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167 cross.pop_back(); |
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168 } |
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169 } |
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170 |
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171 int operator[](int idx) const { |
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172 return cross[idx]; |
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173 } |
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174 |
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175 int operator()(int fdx) const { |
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176 return items[fdx].index; |
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177 } |
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178 |
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179 void firstItem(int& fdx) const { |
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180 fdx = first_item; |
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181 } |
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182 |
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183 void nextItem(int& fdx) const { |
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184 fdx = items[fdx].next; |
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185 } |
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186 |
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187 }; |
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188 } |
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189 } |
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190 |
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191 #endif |