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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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_STATIC_GRAPH_H |
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20 | #define LEMON_STATIC_GRAPH_H |
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21 | |
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22 | ///\ingroup graphs |
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23 | ///\file |
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24 | ///\brief StaticDigraph class. |
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25 | |
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26 | #include <lemon/core.h> |
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27 | #include <lemon/bits/graph_extender.h> |
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28 | |
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29 | namespace lemon { |
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30 | |
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31 | class StaticDigraphBase { |
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32 | public: |
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33 | |
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34 | StaticDigraphBase() |
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35 | : built(false), node_num(0), arc_num(0), |
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36 | node_first_out(NULL), node_first_in(NULL), |
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37 | arc_source(NULL), arc_target(NULL), |
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38 | arc_next_in(NULL), arc_next_out(NULL) {} |
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39 | |
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40 | ~StaticDigraphBase() { |
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41 | if (built) { |
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42 | delete[] node_first_out; |
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43 | delete[] node_first_in; |
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44 | delete[] arc_source; |
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45 | delete[] arc_target; |
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46 | delete[] arc_next_out; |
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47 | delete[] arc_next_in; |
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48 | } |
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49 | } |
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50 | |
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51 | class Node { |
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52 | friend class StaticDigraphBase; |
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53 | protected: |
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54 | int id; |
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55 | Node(int _id) : id(_id) {} |
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56 | public: |
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57 | Node() {} |
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58 | Node (Invalid) : id(-1) {} |
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59 | bool operator==(const Node& node) const { return id == node.id; } |
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60 | bool operator!=(const Node& node) const { return id != node.id; } |
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61 | bool operator<(const Node& node) const { return id < node.id; } |
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62 | }; |
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63 | |
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64 | class Arc { |
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65 | friend class StaticDigraphBase; |
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66 | protected: |
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67 | int id; |
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68 | Arc(int _id) : id(_id) {} |
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69 | public: |
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70 | Arc() { } |
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71 | Arc (Invalid) : id(-1) {} |
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72 | bool operator==(const Arc& arc) const { return id == arc.id; } |
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73 | bool operator!=(const Arc& arc) const { return id != arc.id; } |
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74 | bool operator<(const Arc& arc) const { return id < arc.id; } |
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75 | }; |
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76 | |
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77 | Node source(const Arc& e) const { return Node(arc_source[e.id]); } |
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78 | Node target(const Arc& e) const { return Node(arc_target[e.id]); } |
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79 | |
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80 | void first(Node& n) const { n.id = node_num - 1; } |
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81 | static void next(Node& n) { --n.id; } |
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82 | |
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83 | void first(Arc& e) const { e.id = arc_num - 1; } |
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84 | static void next(Arc& e) { --e.id; } |
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85 | |
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86 | void firstOut(Arc& e, const Node& n) const { |
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87 | e.id = node_first_out[n.id] != node_first_out[n.id + 1] ? |
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88 | node_first_out[n.id] : -1; |
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89 | } |
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90 | void nextOut(Arc& e) const { e.id = arc_next_out[e.id]; } |
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91 | |
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92 | void firstIn(Arc& e, const Node& n) const { e.id = node_first_in[n.id]; } |
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93 | void nextIn(Arc& e) const { e.id = arc_next_in[e.id]; } |
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94 | |
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95 | static int id(const Node& n) { return n.id; } |
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96 | static Node nodeFromId(int id) { return Node(id); } |
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97 | int maxNodeId() const { return node_num - 1; } |
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98 | |
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99 | static int id(const Arc& e) { return e.id; } |
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100 | static Arc arcFromId(int id) { return Arc(id); } |
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101 | int maxArcId() const { return arc_num - 1; } |
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102 | |
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103 | typedef True NodeNumTag; |
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104 | typedef True ArcNumTag; |
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105 | |
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106 | int nodeNum() const { return node_num; } |
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107 | int arcNum() const { return arc_num; } |
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108 | |
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109 | private: |
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110 | |
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111 | template <typename Digraph, typename NodeRefMap> |
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112 | class ArcLess { |
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113 | public: |
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114 | typedef typename Digraph::Arc Arc; |
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115 | |
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116 | ArcLess(const Digraph &_graph, const NodeRefMap& _nodeRef) |
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117 | : digraph(_graph), nodeRef(_nodeRef) {} |
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118 | |
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119 | bool operator()(const Arc& left, const Arc& right) const { |
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120 | return nodeRef[digraph.target(left)] < nodeRef[digraph.target(right)]; |
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121 | } |
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122 | private: |
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123 | const Digraph& digraph; |
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124 | const NodeRefMap& nodeRef; |
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125 | }; |
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126 | |
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127 | public: |
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128 | |
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129 | typedef True BuildTag; |
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130 | |
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131 | void clear() { |
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132 | if (built) { |
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133 | delete[] node_first_out; |
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134 | delete[] node_first_in; |
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135 | delete[] arc_source; |
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136 | delete[] arc_target; |
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137 | delete[] arc_next_out; |
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138 | delete[] arc_next_in; |
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139 | } |
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140 | built = false; |
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141 | node_num = 0; |
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142 | arc_num = 0; |
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143 | } |
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144 | |
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145 | template <typename Digraph, typename NodeRefMap, typename ArcRefMap> |
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146 | void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { |
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147 | typedef typename Digraph::Node GNode; |
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148 | typedef typename Digraph::Arc GArc; |
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149 | |
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150 | built = true; |
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151 | |
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152 | node_num = countNodes(digraph); |
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153 | arc_num = countArcs(digraph); |
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154 | |
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155 | node_first_out = new int[node_num + 1]; |
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156 | node_first_in = new int[node_num]; |
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157 | |
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158 | arc_source = new int[arc_num]; |
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159 | arc_target = new int[arc_num]; |
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160 | arc_next_out = new int[arc_num]; |
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161 | arc_next_in = new int[arc_num]; |
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162 | |
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163 | int node_index = 0; |
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164 | for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { |
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165 | nodeRef[n] = Node(node_index); |
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166 | node_first_in[node_index] = -1; |
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167 | ++node_index; |
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168 | } |
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169 | |
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170 | ArcLess<Digraph, NodeRefMap> arcLess(digraph, nodeRef); |
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171 | |
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172 | int arc_index = 0; |
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173 | for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { |
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174 | int source = nodeRef[n].id; |
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175 | std::vector<GArc> arcs; |
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176 | for (typename Digraph::OutArcIt e(digraph, n); e != INVALID; ++e) { |
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177 | arcs.push_back(e); |
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178 | } |
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179 | if (!arcs.empty()) { |
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180 | node_first_out[source] = arc_index; |
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181 | std::sort(arcs.begin(), arcs.end(), arcLess); |
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182 | for (typename std::vector<GArc>::iterator it = arcs.begin(); |
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183 | it != arcs.end(); ++it) { |
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184 | int target = nodeRef[digraph.target(*it)].id; |
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185 | arcRef[*it] = Arc(arc_index); |
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186 | arc_source[arc_index] = source; |
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187 | arc_target[arc_index] = target; |
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188 | arc_next_in[arc_index] = node_first_in[target]; |
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189 | node_first_in[target] = arc_index; |
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190 | arc_next_out[arc_index] = arc_index + 1; |
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191 | ++arc_index; |
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192 | } |
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193 | arc_next_out[arc_index - 1] = -1; |
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194 | } else { |
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195 | node_first_out[source] = arc_index; |
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196 | } |
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197 | } |
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198 | node_first_out[node_num] = arc_num; |
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199 | } |
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200 | |
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201 | protected: |
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202 | |
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203 | void fastFirstOut(Arc& e, const Node& n) const { |
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204 | e.id = node_first_out[n.id]; |
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205 | } |
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206 | |
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207 | static void fastNextOut(Arc& e) { |
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208 | ++e.id; |
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209 | } |
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210 | void fastLastOut(Arc& e, const Node& n) const { |
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211 | e.id = node_first_out[n.id + 1]; |
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212 | } |
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213 | |
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214 | protected: |
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215 | bool built; |
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216 | int node_num; |
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217 | int arc_num; |
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218 | int *node_first_out; |
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219 | int *node_first_in; |
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220 | int *arc_source; |
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221 | int *arc_target; |
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222 | int *arc_next_in; |
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223 | int *arc_next_out; |
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224 | }; |
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225 | |
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226 | typedef DigraphExtender<StaticDigraphBase> ExtendedStaticDigraphBase; |
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227 | |
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228 | |
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229 | /// \ingroup graphs |
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230 | /// |
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231 | /// \brief A static directed graph class. |
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232 | /// |
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233 | /// \ref StaticDigraph is a highly efficient digraph implementation, |
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234 | /// but it is fully static. |
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235 | /// It stores only two \c int values for each node and only four \c int |
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236 | /// values for each arc. Moreover it provides faster item iteration than |
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237 | /// \ref ListDigraph and \ref SmartDigraph, especially using \c OutArcIt |
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238 | /// iterators, since its arcs are stored in an appropriate order. |
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239 | /// However it only provides build() and clear() functions and does not |
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240 | /// support any other modification of the digraph. |
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241 | /// |
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242 | /// Since this digraph structure is completely static, its nodes and arcs |
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243 | /// can be indexed with integers from the ranges <tt>[0..nodeNum()-1]</tt> |
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244 | /// and <tt>[0..arcNum()-1]</tt>, respectively. |
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245 | /// The index of an item is the same as its ID, it can be obtained |
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246 | /// using the corresponding \ref index() or \ref concepts::Digraph::id() |
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247 | /// "id()" function. A node or arc with a certain index can be obtained |
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248 | /// using node() or arc(). |
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249 | /// |
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250 | /// This type fully conforms to the \ref concepts::Digraph "Digraph concept". |
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251 | /// Most of its member functions and nested classes are documented |
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252 | /// only in the concept class. |
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253 | /// |
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254 | /// \sa concepts::Digraph |
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255 | class StaticDigraph : public ExtendedStaticDigraphBase { |
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256 | public: |
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257 | |
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258 | typedef ExtendedStaticDigraphBase Parent; |
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259 | |
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260 | public: |
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261 | |
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262 | /// \brief Constructor |
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263 | /// |
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264 | /// Default constructor. |
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265 | StaticDigraph() : Parent() {} |
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266 | |
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267 | /// \brief The node with the given index. |
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268 | /// |
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269 | /// This function returns the node with the given index. |
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270 | /// \sa index() |
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271 | static Node node(int ix) { return Parent::nodeFromId(ix); } |
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272 | |
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273 | /// \brief The arc with the given index. |
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274 | /// |
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275 | /// This function returns the arc with the given index. |
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276 | /// \sa index() |
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277 | static Arc arc(int ix) { return Parent::arcFromId(ix); } |
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278 | |
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279 | /// \brief The index of the given node. |
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280 | /// |
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281 | /// This function returns the index of the the given node. |
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282 | /// \sa node() |
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283 | static int index(Node node) { return Parent::id(node); } |
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284 | |
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285 | /// \brief The index of the given arc. |
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286 | /// |
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287 | /// This function returns the index of the the given arc. |
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288 | /// \sa arc() |
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289 | static int index(Arc arc) { return Parent::id(arc); } |
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290 | |
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291 | /// \brief Number of nodes. |
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292 | /// |
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293 | /// This function returns the number of nodes. |
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294 | int nodeNum() const { return node_num; } |
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295 | |
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296 | /// \brief Number of arcs. |
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297 | /// |
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298 | /// This function returns the number of arcs. |
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299 | int arcNum() const { return arc_num; } |
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300 | |
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301 | /// \brief Build the digraph copying another digraph. |
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302 | /// |
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303 | /// This function builds the digraph copying another digraph of any |
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304 | /// kind. It can be called more than once, but in such case, the whole |
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305 | /// structure and all maps will be cleared and rebuilt. |
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306 | /// |
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307 | /// This method also makes possible to copy a digraph to a StaticDigraph |
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308 | /// structure using \ref DigraphCopy. |
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309 | /// |
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310 | /// \param digraph An existing digraph to be copied. |
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311 | /// \param nodeRef The node references will be copied into this map. |
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312 | /// Its key type must be \c Digraph::Node and its value type must be |
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313 | /// \c StaticDigraph::Node. |
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314 | /// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" |
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315 | /// concept. |
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316 | /// \param arcRef The arc references will be copied into this map. |
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317 | /// Its key type must be \c Digraph::Arc and its value type must be |
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318 | /// \c StaticDigraph::Arc. |
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319 | /// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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320 | /// |
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321 | /// \note If you do not need the arc references, then you could use |
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322 | /// \ref NullMap for the last parameter. However the node references |
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323 | /// are required by the function itself, thus they must be readable |
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324 | /// from the map. |
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325 | template <typename Digraph, typename NodeRefMap, typename ArcRefMap> |
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326 | void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { |
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327 | if (built) Parent::clear(); |
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328 | Parent::build(digraph, nodeRef, arcRef); |
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329 | } |
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330 | |
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331 | /// \brief Clear the digraph. |
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332 | /// |
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333 | /// This function erases all nodes and arcs from the digraph. |
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334 | void clear() { |
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335 | Parent::clear(); |
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336 | } |
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337 | |
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338 | protected: |
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339 | |
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340 | using Parent::fastFirstOut; |
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341 | using Parent::fastNextOut; |
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342 | using Parent::fastLastOut; |
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343 | |
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344 | public: |
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345 | |
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346 | class OutArcIt : public Arc { |
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347 | public: |
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348 | |
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349 | OutArcIt() { } |
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350 | |
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351 | OutArcIt(Invalid i) : Arc(i) { } |
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352 | |
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353 | OutArcIt(const StaticDigraph& digraph, const Node& node) { |
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354 | digraph.fastFirstOut(*this, node); |
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355 | digraph.fastLastOut(last, node); |
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356 | if (last == *this) *this = INVALID; |
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357 | } |
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358 | |
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359 | OutArcIt(const StaticDigraph& digraph, const Arc& arc) : Arc(arc) { |
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360 | if (arc != INVALID) { |
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361 | digraph.fastLastOut(last, digraph.source(arc)); |
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362 | } |
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363 | } |
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364 | |
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365 | OutArcIt& operator++() { |
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366 | StaticDigraph::fastNextOut(*this); |
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367 | if (last == *this) *this = INVALID; |
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368 | return *this; |
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369 | } |
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370 | |
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371 | private: |
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372 | Arc last; |
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373 | }; |
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374 | |
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375 | Node baseNode(const OutArcIt &arc) const { |
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376 | return Parent::source(static_cast<const Arc&>(arc)); |
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377 | } |
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378 | |
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379 | Node runningNode(const OutArcIt &arc) const { |
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380 | return Parent::target(static_cast<const Arc&>(arc)); |
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381 | } |
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382 | |
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383 | Node baseNode(const InArcIt &arc) const { |
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384 | return Parent::target(static_cast<const Arc&>(arc)); |
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385 | } |
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386 | |
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387 | Node runningNode(const InArcIt &arc) const { |
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388 | return Parent::source(static_cast<const Arc&>(arc)); |
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389 | } |
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390 | |
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391 | }; |
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392 | |
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393 | } |
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394 | |
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395 | #endif |
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