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) 2003-2006 |
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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 | ///\ingroup concept |
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20 | ///\file |
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21 | ///\brief Classes for representing paths in graphs. |
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22 | /// |
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23 | ///\todo Iterators have obsolete style |
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24 | |
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25 | #ifndef LEMON_CONCEPT_PATH_H |
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26 | #define LEMON_CONCEPT_PATH_H |
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27 | |
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28 | #include <lemon/bits/invalid.h> |
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29 | #include <lemon/concept_check.h> |
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30 | |
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31 | namespace lemon { |
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32 | namespace concept { |
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33 | /// \addtogroup concept |
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34 | /// @{ |
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35 | |
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36 | |
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37 | //! \brief A skeleton structure for representing directed paths in a graph. |
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38 | //! |
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39 | //! A skeleton structure for representing directed paths in a graph. |
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40 | //! \param _Graph The graph type in which the path is. |
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41 | //! |
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42 | //! In a sense, the path can be treated as a graph, for it has \c NodeIt |
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43 | //! and \c EdgeIt with the same usage. These types converts to the \c Node |
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44 | //! and \c Edge of the original graph. |
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45 | template<typename _Graph> |
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46 | class Path { |
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47 | public: |
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48 | |
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49 | /// Type of the underlying graph. |
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50 | typedef _Graph Graph; |
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51 | /// Edge type of the underlying graph. |
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52 | typedef typename Graph::Edge Edge; |
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53 | /// Node type of the underlying graph. |
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54 | typedef typename Graph::Node Node; |
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55 | |
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56 | class NodeIt; |
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57 | class EdgeIt; |
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58 | |
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59 | /// \param _g The graph in which the path is. |
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60 | /// |
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61 | Path(const Graph &_g) { |
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62 | ignore_unused_variable_warning(_g); |
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63 | } |
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64 | |
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65 | /// Length of the path ie. the number of edges in the path. |
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66 | int length() const {return 0;} |
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67 | |
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68 | /// Returns whether the path is empty. |
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69 | bool empty() const { return true;} |
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70 | |
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71 | /// Resets the path to an empty path. |
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72 | void clear() {} |
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73 | |
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74 | /// \brief Starting point of the path. |
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75 | /// |
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76 | /// Starting point of the path. |
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77 | /// Returns INVALID if the path is empty. |
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78 | Node target() const {return INVALID;} |
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79 | /// \brief End point of the path. |
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80 | /// |
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81 | /// End point of the path. |
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82 | /// Returns INVALID if the path is empty. |
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83 | Node source() const {return INVALID;} |
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84 | |
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85 | /// \brief The target of an edge. |
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86 | /// |
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87 | /// Returns node iterator pointing to the target node of the |
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88 | /// given edge iterator. |
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89 | NodeIt target(const EdgeIt&) const {return INVALID;} |
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90 | |
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91 | /// \brief The source of an edge. |
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92 | /// |
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93 | /// Returns node iterator pointing to the source node of the |
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94 | /// given edge iterator. |
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95 | NodeIt source(const EdgeIt&) const {return INVALID;} |
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96 | |
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97 | /// \brief Iterator class to iterate on the nodes of the paths |
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98 | /// |
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99 | /// This class is used to iterate on the nodes of the paths |
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100 | /// |
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101 | /// Of course it converts to Graph::Node. |
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102 | class NodeIt { |
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103 | public: |
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104 | /// Default constructor |
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105 | NodeIt() {} |
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106 | /// Invalid constructor |
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107 | NodeIt(Invalid) {} |
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108 | /// Constructor with starting point |
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109 | NodeIt(const Path &) {} |
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110 | |
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111 | ///Conversion to Graph::Node |
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112 | operator Node() const { return INVALID; } |
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113 | /// Next node |
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114 | NodeIt& operator++() {return *this;} |
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115 | |
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116 | /// Comparison operator |
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117 | bool operator==(const NodeIt&) const {return true;} |
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118 | /// Comparison operator |
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119 | bool operator!=(const NodeIt&) const {return true;} |
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120 | /// Comparison operator |
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121 | bool operator<(const NodeIt&) const {return false;} |
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122 | |
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123 | }; |
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124 | |
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125 | /// \brief Iterator class to iterate on the edges of the paths |
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126 | /// |
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127 | /// This class is used to iterate on the edges of the paths |
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128 | /// |
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129 | /// Of course it converts to Graph::Edge |
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130 | class EdgeIt { |
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131 | public: |
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132 | /// Default constructor |
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133 | EdgeIt() {} |
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134 | /// Invalid constructor |
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135 | EdgeIt(Invalid) {} |
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136 | /// Constructor with starting point |
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137 | EdgeIt(const Path &) {} |
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138 | |
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139 | operator Edge() const { return INVALID; } |
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140 | |
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141 | /// Next edge |
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142 | EdgeIt& operator++() {return *this;} |
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143 | |
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144 | /// Comparison operator |
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145 | bool operator==(const EdgeIt&) const {return true;} |
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146 | /// Comparison operator |
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147 | bool operator!=(const EdgeIt&) const {return true;} |
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148 | /// Comparison operator |
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149 | bool operator<(const EdgeIt&) const {return false;} |
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150 | |
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151 | }; |
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152 | |
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153 | |
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154 | friend class Builder; |
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155 | |
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156 | /// \brief Class to build paths |
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157 | /// |
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158 | /// This class is used to fill a path with edges. |
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159 | /// |
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160 | /// You can push new edges to the front and to the back of the path in |
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161 | /// arbitrary order then you should commit these changes to the graph. |
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162 | /// |
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163 | /// While the builder is active (after the first modifying |
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164 | /// operation and until the call of \ref commit()) the |
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165 | /// underlining Path is in a "transitional" state (operations on |
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166 | /// it have undefined result). |
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167 | class Builder { |
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168 | public: |
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169 | |
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170 | /// Constructor |
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171 | |
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172 | /// Constructor |
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173 | /// \param _path the path you want to fill in. |
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174 | /// |
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175 | |
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176 | Builder(Path &_path) { ignore_unused_variable_warning(_path); } |
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177 | |
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178 | /// Sets the starting node of the path. |
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179 | |
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180 | /// Sets the starting node of the path. Edge added to the path |
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181 | /// afterwards have to be incident to this node. |
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182 | /// You \em must start building an empty path with these functions. |
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183 | /// (And you \em must \em not use it later). |
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184 | /// \sa pushFront() |
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185 | /// \sa pushBack() |
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186 | void setStartNode(const Node &) {} |
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187 | |
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188 | ///Push a new edge to the front of the path |
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189 | |
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190 | ///Push a new edge to the front of the path. |
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191 | ///If the path is empty, you \em must call \ref setStartNode() before |
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192 | ///the first use of \ref pushFront(). |
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193 | void pushFront(const Edge&) {} |
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194 | |
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195 | ///Push a new edge to the back of the path |
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196 | |
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197 | ///Push a new edge to the back of the path. |
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198 | ///If the path is empty, you \em must call \ref setStartNode() before |
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199 | ///the first use of \ref pushBack(). |
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200 | void pushBack(const Edge&) {} |
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201 | |
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202 | ///Commit the changes to the path. |
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203 | |
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204 | ///Commit the changes to the path. |
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205 | /// |
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206 | void commit() {} |
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207 | |
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208 | ///Reserve (front) storage for the builder in advance. |
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209 | |
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210 | ///If you know a reasonable upper bound on the number of the edges |
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211 | ///to add to the front of the path, |
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212 | ///using this function you may speed up the building. |
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213 | void reserveFront(size_t) {} |
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214 | ///Reserve (back) storage for the builder in advance. |
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215 | |
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216 | ///If you know a reasonable upper bound on the number of the edges |
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217 | ///to add to the back of the path, |
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218 | ///using this function you may speed up the building. |
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219 | void reserveBack(size_t) {} |
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220 | }; |
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221 | |
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222 | template <typename _Path> |
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223 | struct Constraints { |
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224 | void constraints() { |
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225 | typedef typename _Path::Node Node; |
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226 | typedef typename _Path::NodeIt NodeIt; |
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227 | typedef typename Graph::Node GraphNode; |
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228 | |
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229 | typedef typename _Path::Edge Edge; |
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230 | typedef typename _Path::EdgeIt EdgeIt; |
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231 | typedef typename Graph::Edge GraphEdge; |
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232 | |
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233 | typedef typename _Path::Builder Builder; |
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234 | |
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235 | path = _Path(graph); |
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236 | |
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237 | bool b = cpath.empty(); |
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238 | int l = cpath.length(); |
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239 | |
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240 | Node gn; |
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241 | Edge ge; |
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242 | gn = cpath.source(); |
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243 | gn = cpath.target(); |
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244 | |
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245 | NodeIt nit; |
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246 | EdgeIt eit(INVALID); |
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247 | nit = path.source(eit); |
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248 | nit = path.target(eit); |
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249 | |
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250 | nit = NodeIt(); |
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251 | nit = NodeIt(cpath); |
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252 | nit = INVALID; |
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253 | gn = nit; |
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254 | ++nit; |
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255 | b = nit == nit; |
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256 | b = nit != nit; |
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257 | b = nit < nit; |
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258 | |
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259 | eit = EdgeIt(); |
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260 | eit = EdgeIt(cpath); |
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261 | eit = INVALID; |
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262 | ge = eit; |
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263 | ++eit; |
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264 | b = eit == eit; |
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265 | b = eit != eit; |
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266 | b = eit < eit; |
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267 | |
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268 | size_t st = 0; |
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269 | |
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270 | Builder builder(path); |
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271 | builder.setStartNode(gn); |
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272 | builder.pushFront(ge); |
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273 | builder.pushBack(ge); |
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274 | builder.commit(); |
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275 | builder.reserveFront(st); |
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276 | builder.reserveBack(st); |
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277 | |
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278 | ignore_unused_variable_warning(l); |
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279 | ignore_unused_variable_warning(b); |
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280 | } |
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281 | |
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282 | const Graph& graph; |
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283 | const _Path& cpath; |
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284 | _Path& path; |
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285 | }; |
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286 | |
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287 | }; |
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288 | |
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289 | ///@} |
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290 | } |
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291 | |
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292 | } // namespace lemon |
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293 | |
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294 | #endif // LEMON_CONCEPT_PATH_H |
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