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) 2003-2010 |
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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 | |
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33 | public: |
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34 | |
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35 | StaticDigraphBase() |
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36 | : built(false), node_num(0), arc_num(0), |
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37 | node_first_out(NULL), node_first_in(NULL), |
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38 | arc_source(NULL), arc_target(NULL), |
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39 | arc_next_in(NULL), arc_next_out(NULL) {} |
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40 | |
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41 | ~StaticDigraphBase() { |
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42 | if (built) { |
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43 | delete[] node_first_out; |
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44 | delete[] node_first_in; |
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45 | delete[] arc_source; |
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46 | delete[] arc_target; |
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47 | delete[] arc_next_out; |
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48 | delete[] arc_next_in; |
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49 | } |
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50 | } |
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51 | |
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52 | class Node { |
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53 | friend class StaticDigraphBase; |
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54 | protected: |
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55 | int id; |
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56 | Node(int _id) : id(_id) {} |
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57 | public: |
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58 | Node() {} |
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59 | Node (Invalid) : id(-1) {} |
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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 | bool operator<(const Node& node) const { return id < node.id; } |
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63 | }; |
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64 | |
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65 | class Arc { |
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66 | friend class StaticDigraphBase; |
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67 | protected: |
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68 | int id; |
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69 | Arc(int _id) : id(_id) {} |
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70 | public: |
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71 | Arc() { } |
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72 | Arc (Invalid) : id(-1) {} |
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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 | bool operator<(const Arc& arc) const { return id < arc.id; } |
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76 | }; |
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77 | |
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78 | Node source(const Arc& e) const { return Node(arc_source[e.id]); } |
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79 | Node target(const Arc& e) const { return Node(arc_target[e.id]); } |
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80 | |
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81 | void first(Node& n) const { n.id = node_num - 1; } |
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82 | static void next(Node& n) { --n.id; } |
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83 | |
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84 | void first(Arc& e) const { e.id = arc_num - 1; } |
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85 | static void next(Arc& e) { --e.id; } |
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86 | |
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87 | void firstOut(Arc& e, const Node& n) const { |
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88 | e.id = node_first_out[n.id] != node_first_out[n.id + 1] ? |
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89 | node_first_out[n.id] : -1; |
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90 | } |
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91 | void nextOut(Arc& e) const { e.id = arc_next_out[e.id]; } |
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92 | |
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93 | void firstIn(Arc& e, const Node& n) const { e.id = node_first_in[n.id]; } |
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94 | void nextIn(Arc& e) const { e.id = arc_next_in[e.id]; } |
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95 | |
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96 | static int id(const Node& n) { return n.id; } |
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97 | static Node nodeFromId(int id) { return Node(id); } |
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98 | int maxNodeId() const { return node_num - 1; } |
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99 | |
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100 | static int id(const Arc& e) { return e.id; } |
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101 | static Arc arcFromId(int id) { return Arc(id); } |
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102 | int maxArcId() const { return arc_num - 1; } |
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103 | |
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104 | typedef True NodeNumTag; |
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105 | typedef True ArcNumTag; |
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106 | |
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107 | int nodeNum() const { return node_num; } |
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108 | int arcNum() const { return arc_num; } |
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109 | |
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110 | private: |
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111 | |
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112 | template <typename Digraph, typename NodeRefMap> |
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113 | class ArcLess { |
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114 | public: |
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115 | typedef typename Digraph::Arc Arc; |
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116 | |
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117 | ArcLess(const Digraph &_graph, const NodeRefMap& _nodeRef) |
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118 | : digraph(_graph), nodeRef(_nodeRef) {} |
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119 | |
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120 | bool operator()(const Arc& left, const Arc& right) const { |
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121 | return nodeRef[digraph.target(left)] < nodeRef[digraph.target(right)]; |
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122 | } |
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123 | private: |
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124 | const Digraph& digraph; |
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125 | const NodeRefMap& nodeRef; |
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126 | }; |
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127 | |
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128 | public: |
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129 | |
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130 | typedef True BuildTag; |
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131 | |
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132 | void clear() { |
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133 | if (built) { |
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134 | delete[] node_first_out; |
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135 | delete[] node_first_in; |
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136 | delete[] arc_source; |
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137 | delete[] arc_target; |
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138 | delete[] arc_next_out; |
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139 | delete[] arc_next_in; |
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140 | } |
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141 | built = false; |
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142 | node_num = 0; |
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143 | arc_num = 0; |
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144 | } |
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145 | |
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146 | template <typename Digraph, typename NodeRefMap, typename ArcRefMap> |
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147 | void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { |
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148 | typedef typename Digraph::Node GNode; |
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149 | typedef typename Digraph::Arc GArc; |
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150 | |
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151 | built = true; |
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152 | |
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153 | node_num = countNodes(digraph); |
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154 | arc_num = countArcs(digraph); |
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155 | |
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156 | node_first_out = new int[node_num + 1]; |
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157 | node_first_in = new int[node_num]; |
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158 | |
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159 | arc_source = new int[arc_num]; |
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160 | arc_target = new int[arc_num]; |
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161 | arc_next_out = new int[arc_num]; |
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162 | arc_next_in = new int[arc_num]; |
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163 | |
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164 | int node_index = 0; |
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165 | for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { |
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166 | nodeRef[n] = Node(node_index); |
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167 | node_first_in[node_index] = -1; |
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168 | ++node_index; |
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169 | } |
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170 | |
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171 | ArcLess<Digraph, NodeRefMap> arcLess(digraph, nodeRef); |
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172 | |
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173 | int arc_index = 0; |
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174 | for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { |
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175 | int source = nodeRef[n].id; |
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176 | std::vector<GArc> arcs; |
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177 | for (typename Digraph::OutArcIt e(digraph, n); e != INVALID; ++e) { |
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178 | arcs.push_back(e); |
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179 | } |
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180 | if (!arcs.empty()) { |
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181 | node_first_out[source] = arc_index; |
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182 | std::sort(arcs.begin(), arcs.end(), arcLess); |
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183 | for (typename std::vector<GArc>::iterator it = arcs.begin(); |
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184 | it != arcs.end(); ++it) { |
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185 | int target = nodeRef[digraph.target(*it)].id; |
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186 | arcRef[*it] = Arc(arc_index); |
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187 | arc_source[arc_index] = source; |
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188 | arc_target[arc_index] = target; |
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189 | arc_next_in[arc_index] = node_first_in[target]; |
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190 | node_first_in[target] = arc_index; |
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191 | arc_next_out[arc_index] = arc_index + 1; |
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192 | ++arc_index; |
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193 | } |
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194 | arc_next_out[arc_index - 1] = -1; |
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195 | } else { |
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196 | node_first_out[source] = arc_index; |
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197 | } |
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198 | } |
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199 | node_first_out[node_num] = arc_num; |
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200 | } |
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201 | |
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202 | template <typename ArcListIterator> |
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203 | void build(int n, ArcListIterator first, ArcListIterator last) { |
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204 | built = true; |
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205 | |
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206 | node_num = n; |
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207 | arc_num = static_cast<int>(std::distance(first, last)); |
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208 | |
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209 | node_first_out = new int[node_num + 1]; |
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210 | node_first_in = new int[node_num]; |
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211 | |
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212 | arc_source = new int[arc_num]; |
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213 | arc_target = new int[arc_num]; |
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214 | arc_next_out = new int[arc_num]; |
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215 | arc_next_in = new int[arc_num]; |
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216 | |
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217 | for (int i = 0; i != node_num; ++i) { |
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218 | node_first_in[i] = -1; |
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219 | } |
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220 | |
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221 | int arc_index = 0; |
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222 | for (int i = 0; i != node_num; ++i) { |
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223 | node_first_out[i] = arc_index; |
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224 | for ( ; first != last && (*first).first == i; ++first) { |
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225 | int j = (*first).second; |
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226 | LEMON_ASSERT(j >= 0 && j < node_num, |
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227 | "Wrong arc list for StaticDigraph::build()"); |
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228 | arc_source[arc_index] = i; |
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229 | arc_target[arc_index] = j; |
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230 | arc_next_in[arc_index] = node_first_in[j]; |
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231 | node_first_in[j] = arc_index; |
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232 | arc_next_out[arc_index] = arc_index + 1; |
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233 | ++arc_index; |
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234 | } |
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235 | if (arc_index > node_first_out[i]) |
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236 | arc_next_out[arc_index - 1] = -1; |
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237 | } |
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238 | LEMON_ASSERT(first == last, |
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239 | "Wrong arc list for StaticDigraph::build()"); |
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240 | node_first_out[node_num] = arc_num; |
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241 | } |
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242 | |
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243 | protected: |
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244 | |
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245 | void fastFirstOut(Arc& e, const Node& n) const { |
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246 | e.id = node_first_out[n.id]; |
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247 | } |
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248 | |
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249 | static void fastNextOut(Arc& e) { |
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250 | ++e.id; |
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251 | } |
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252 | void fastLastOut(Arc& e, const Node& n) const { |
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253 | e.id = node_first_out[n.id + 1]; |
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254 | } |
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255 | |
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256 | protected: |
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257 | bool built; |
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258 | int node_num; |
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259 | int arc_num; |
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260 | int *node_first_out; |
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261 | int *node_first_in; |
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262 | int *arc_source; |
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263 | int *arc_target; |
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264 | int *arc_next_in; |
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265 | int *arc_next_out; |
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266 | }; |
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267 | |
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268 | typedef DigraphExtender<StaticDigraphBase> ExtendedStaticDigraphBase; |
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269 | |
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270 | |
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271 | /// \ingroup graphs |
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272 | /// |
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273 | /// \brief A static directed graph class. |
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274 | /// |
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275 | /// \ref StaticDigraph is a highly efficient digraph implementation, |
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276 | /// but it is fully static. |
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277 | /// It stores only two \c int values for each node and only four \c int |
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278 | /// values for each arc. Moreover it provides faster item iteration than |
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279 | /// \ref ListDigraph and \ref SmartDigraph, especially using \c OutArcIt |
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280 | /// iterators, since its arcs are stored in an appropriate order. |
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281 | /// However it only provides build() and clear() functions and does not |
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282 | /// support any other modification of the digraph. |
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283 | /// |
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284 | /// Since this digraph structure is completely static, its nodes and arcs |
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285 | /// can be indexed with integers from the ranges <tt>[0..nodeNum()-1]</tt> |
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286 | /// and <tt>[0..arcNum()-1]</tt>, respectively. |
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287 | /// The index of an item is the same as its ID, it can be obtained |
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288 | /// using the corresponding \ref index() or \ref concepts::Digraph::id() |
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289 | /// "id()" function. A node or arc with a certain index can be obtained |
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290 | /// using node() or arc(). |
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291 | /// |
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292 | /// This type fully conforms to the \ref concepts::Digraph "Digraph concept". |
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293 | /// Most of its member functions and nested classes are documented |
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294 | /// only in the concept class. |
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295 | /// |
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296 | /// This class provides constant time counting for nodes and arcs. |
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297 | /// |
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298 | /// \sa concepts::Digraph |
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299 | class StaticDigraph : public ExtendedStaticDigraphBase { |
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300 | |
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301 | private: |
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302 | /// Graphs are \e not copy constructible. Use DigraphCopy instead. |
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303 | StaticDigraph(const StaticDigraph &) : ExtendedStaticDigraphBase() {}; |
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304 | /// \brief Assignment of a graph to another one is \e not allowed. |
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305 | /// Use DigraphCopy instead. |
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306 | void operator=(const StaticDigraph&) {} |
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307 | |
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308 | public: |
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309 | |
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310 | typedef ExtendedStaticDigraphBase Parent; |
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311 | |
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312 | public: |
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313 | |
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314 | /// \brief Constructor |
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315 | /// |
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316 | /// Default constructor. |
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317 | StaticDigraph() : Parent() {} |
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318 | |
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319 | /// \brief The node with the given index. |
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320 | /// |
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321 | /// This function returns the node with the given index. |
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322 | /// \sa index() |
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323 | static Node node(int ix) { return Parent::nodeFromId(ix); } |
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324 | |
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325 | /// \brief The arc with the given index. |
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326 | /// |
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327 | /// This function returns the arc with the given index. |
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328 | /// \sa index() |
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329 | static Arc arc(int ix) { return Parent::arcFromId(ix); } |
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330 | |
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331 | /// \brief The index of the given node. |
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332 | /// |
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333 | /// This function returns the index of the the given node. |
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334 | /// \sa node() |
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335 | static int index(Node node) { return Parent::id(node); } |
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336 | |
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337 | /// \brief The index of the given arc. |
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338 | /// |
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339 | /// This function returns the index of the the given arc. |
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340 | /// \sa arc() |
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341 | static int index(Arc arc) { return Parent::id(arc); } |
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342 | |
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343 | /// \brief Number of nodes. |
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344 | /// |
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345 | /// This function returns the number of nodes. |
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346 | int nodeNum() const { return node_num; } |
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347 | |
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348 | /// \brief Number of arcs. |
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349 | /// |
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350 | /// This function returns the number of arcs. |
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351 | int arcNum() const { return arc_num; } |
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352 | |
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353 | /// \brief Build the digraph copying another digraph. |
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354 | /// |
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355 | /// This function builds the digraph copying another digraph of any |
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356 | /// kind. It can be called more than once, but in such case, the whole |
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357 | /// structure and all maps will be cleared and rebuilt. |
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358 | /// |
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359 | /// This method also makes possible to copy a digraph to a StaticDigraph |
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360 | /// structure using \ref DigraphCopy. |
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361 | /// |
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362 | /// \param digraph An existing digraph to be copied. |
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363 | /// \param nodeRef The node references will be copied into this map. |
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364 | /// Its key type must be \c Digraph::Node and its value type must be |
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365 | /// \c StaticDigraph::Node. |
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366 | /// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" |
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367 | /// concept. |
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368 | /// \param arcRef The arc references will be copied into this map. |
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369 | /// Its key type must be \c Digraph::Arc and its value type must be |
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370 | /// \c StaticDigraph::Arc. |
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371 | /// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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372 | /// |
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373 | /// \note If you do not need the arc references, then you could use |
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374 | /// \ref NullMap for the last parameter. However the node references |
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375 | /// are required by the function itself, thus they must be readable |
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376 | /// from the map. |
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377 | template <typename Digraph, typename NodeRefMap, typename ArcRefMap> |
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378 | void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { |
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379 | if (built) Parent::clear(); |
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380 | Parent::build(digraph, nodeRef, arcRef); |
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381 | } |
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382 | |
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383 | /// \brief Build the digraph from an arc list. |
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384 | /// |
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385 | /// This function builds the digraph from the given arc list. |
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386 | /// It can be called more than once, but in such case, the whole |
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387 | /// structure and all maps will be cleared and rebuilt. |
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388 | /// |
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389 | /// The list of the arcs must be given in the range <tt>[begin, end)</tt> |
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390 | /// specified by STL compatible itartors whose \c value_type must be |
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391 | /// <tt>std::pair<int,int></tt>. |
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392 | /// Each arc must be specified by a pair of integer indices |
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393 | /// from the range <tt>[0..n-1]</tt>. <i>The pairs must be in a |
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394 | /// non-decreasing order with respect to their first values.</i> |
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395 | /// If the k-th pair in the list is <tt>(i,j)</tt>, then |
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396 | /// <tt>arc(k-1)</tt> will connect <tt>node(i)</tt> to <tt>node(j)</tt>. |
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397 | /// |
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398 | /// \param n The number of nodes. |
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399 | /// \param begin An iterator pointing to the beginning of the arc list. |
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400 | /// \param end An iterator pointing to the end of the arc list. |
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401 | /// |
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402 | /// For example, a simple digraph can be constructed like this. |
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403 | /// \code |
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404 | /// std::vector<std::pair<int,int> > arcs; |
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405 | /// arcs.push_back(std::make_pair(0,1)); |
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406 | /// arcs.push_back(std::make_pair(0,2)); |
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407 | /// arcs.push_back(std::make_pair(1,3)); |
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408 | /// arcs.push_back(std::make_pair(1,2)); |
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409 | /// arcs.push_back(std::make_pair(3,0)); |
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410 | /// StaticDigraph gr; |
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411 | /// gr.build(4, arcs.begin(), arcs.end()); |
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412 | /// \endcode |
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413 | template <typename ArcListIterator> |
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414 | void build(int n, ArcListIterator begin, ArcListIterator end) { |
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415 | if (built) Parent::clear(); |
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416 | StaticDigraphBase::build(n, begin, end); |
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417 | notifier(Node()).build(); |
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418 | notifier(Arc()).build(); |
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419 | } |
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420 | |
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421 | /// \brief Clear the digraph. |
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422 | /// |
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423 | /// This function erases all nodes and arcs from the digraph. |
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424 | void clear() { |
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425 | Parent::clear(); |
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426 | } |
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427 | |
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428 | protected: |
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429 | |
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430 | using Parent::fastFirstOut; |
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431 | using Parent::fastNextOut; |
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432 | using Parent::fastLastOut; |
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433 | |
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434 | public: |
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435 | |
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436 | class OutArcIt : public Arc { |
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437 | public: |
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438 | |
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439 | OutArcIt() { } |
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440 | |
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441 | OutArcIt(Invalid i) : Arc(i) { } |
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442 | |
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443 | OutArcIt(const StaticDigraph& digraph, const Node& node) { |
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444 | digraph.fastFirstOut(*this, node); |
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445 | digraph.fastLastOut(last, node); |
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446 | if (last == *this) *this = INVALID; |
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447 | } |
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448 | |
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449 | OutArcIt(const StaticDigraph& digraph, const Arc& arc) : Arc(arc) { |
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450 | if (arc != INVALID) { |
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451 | digraph.fastLastOut(last, digraph.source(arc)); |
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452 | } |
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453 | } |
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454 | |
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455 | OutArcIt& operator++() { |
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456 | StaticDigraph::fastNextOut(*this); |
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457 | if (last == *this) *this = INVALID; |
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458 | return *this; |
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459 | } |
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460 | |
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461 | private: |
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462 | Arc last; |
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463 | }; |
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464 | |
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465 | Node baseNode(const OutArcIt &arc) const { |
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466 | return Parent::source(static_cast<const Arc&>(arc)); |
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467 | } |
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468 | |
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469 | Node runningNode(const OutArcIt &arc) const { |
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470 | return Parent::target(static_cast<const Arc&>(arc)); |
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471 | } |
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472 | |
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473 | Node baseNode(const InArcIt &arc) const { |
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474 | return Parent::target(static_cast<const Arc&>(arc)); |
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475 | } |
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476 | |
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477 | Node runningNode(const InArcIt &arc) const { |
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478 | return Parent::source(static_cast<const Arc&>(arc)); |
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479 | } |
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480 | |
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481 | }; |
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482 | |
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483 | } |
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484 | |
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485 | #endif |
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