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) 2003-2013 |
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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 paths |
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20 | ///\file |
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21 | ///\brief Classes for representing paths in digraphs. |
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22 | /// |
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23 | |
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24 | #ifndef LEMON_PATH_H |
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25 | #define LEMON_PATH_H |
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26 | |
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27 | #include <vector> |
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28 | #include <algorithm> |
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29 | |
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30 | #include <lemon/error.h> |
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31 | #include <lemon/core.h> |
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32 | #include <lemon/concepts/path.h> |
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33 | #include <lemon/bits/stl_iterators.h> |
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34 | |
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35 | namespace lemon { |
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36 | |
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37 | /// \addtogroup paths |
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38 | /// @{ |
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39 | |
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40 | |
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41 | /// \brief A structure for representing directed paths in a digraph. |
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42 | /// |
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43 | /// A structure for representing directed path in a digraph. |
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44 | /// \tparam GR The digraph type in which the path is. |
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45 | /// |
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46 | /// In a sense, a path can be treated as a list of arcs. The |
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47 | /// LEMON path type simply stores this list. As a consequence, it |
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48 | /// cannot enumerate the nodes in the path, and the source node of |
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49 | /// a zero-length path is undefined. |
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50 | /// |
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51 | /// This implementation is a back and front insertable and erasable |
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52 | /// path type. It can be indexed in O(1) time. The front and back |
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53 | /// insertion and erase is done in O(1) (amortized) time. The |
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54 | /// implementation uses two vectors for storing the front and back |
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55 | /// insertions. |
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56 | template <typename GR> |
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57 | class Path { |
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58 | public: |
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59 | |
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60 | typedef GR Digraph; |
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61 | typedef typename Digraph::Arc Arc; |
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62 | |
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63 | /// \brief Default constructor |
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64 | /// |
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65 | /// Default constructor |
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66 | Path() {} |
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67 | |
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68 | /// \brief Copy constructor |
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69 | /// |
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70 | Path(const Path& cpath) { |
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71 | pathCopy(cpath, *this); |
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72 | } |
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73 | |
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74 | /// \brief Template copy constructor |
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75 | /// |
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76 | /// This constuctor initializes the path from any other path type. |
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77 | /// It simply makes a copy of the given path. |
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78 | template <typename CPath> |
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79 | Path(const CPath& cpath) { |
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80 | pathCopy(cpath, *this); |
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81 | } |
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82 | |
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83 | /// \brief Copy assignment |
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84 | /// |
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85 | Path& operator=(const Path& cpath) { |
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86 | pathCopy(cpath, *this); |
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87 | return *this; |
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88 | } |
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89 | |
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90 | /// \brief Template copy assignment |
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91 | /// |
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92 | /// This operator makes a copy of a path of any other type. |
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93 | template <typename CPath> |
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94 | Path& operator=(const CPath& cpath) { |
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95 | pathCopy(cpath, *this); |
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96 | return *this; |
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97 | } |
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98 | |
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99 | /// \brief LEMON style iterator for path arcs |
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100 | /// |
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101 | /// This class is used to iterate on the arcs of the paths. |
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102 | class ArcIt { |
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103 | friend class Path; |
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104 | public: |
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105 | /// \brief Default constructor |
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106 | ArcIt() {} |
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107 | /// \brief Invalid constructor |
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108 | ArcIt(Invalid) : path(0), idx(-1) {} |
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109 | /// \brief Initializate the iterator to the first arc of path |
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110 | ArcIt(const Path &_path) |
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111 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
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112 | |
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113 | private: |
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114 | |
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115 | ArcIt(const Path &_path, int _idx) |
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116 | : path(&_path), idx(_idx) {} |
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117 | |
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118 | public: |
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119 | |
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120 | /// \brief Conversion to Arc |
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121 | operator const Arc&() const { |
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122 | return path->nth(idx); |
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123 | } |
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124 | |
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125 | /// \brief Next arc |
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126 | ArcIt& operator++() { |
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127 | ++idx; |
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128 | if (idx >= path->length()) idx = -1; |
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129 | return *this; |
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130 | } |
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131 | |
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132 | /// \brief Comparison operator |
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133 | bool operator==(const ArcIt& e) const { return idx==e.idx; } |
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134 | /// \brief Comparison operator |
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135 | bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
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136 | /// \brief Comparison operator |
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137 | bool operator<(const ArcIt& e) const { return idx<e.idx; } |
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138 | |
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139 | private: |
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140 | const Path *path; |
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141 | int idx; |
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142 | }; |
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143 | |
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144 | /// \brief Gets the collection of the arcs of the path. |
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145 | /// |
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146 | /// This function can be used for iterating on the |
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147 | /// arcs of the path. It returns a wrapped |
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148 | /// ArcIt, which looks like an STL container |
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149 | /// (by having begin() and end()) which you can use in range-based |
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150 | /// for loops, STL algorithms, etc. |
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151 | /// For example you can write: |
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152 | ///\code |
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153 | /// for(auto a: p.arcs()) |
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154 | /// doSomething(a); |
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155 | ///\endcode |
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156 | LemonRangeWrapper1<ArcIt, Path> arcs() const { |
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157 | return LemonRangeWrapper1<ArcIt, Path>(*this); |
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158 | } |
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159 | |
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160 | |
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161 | /// \brief Length of the path. |
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162 | int length() const { return head.size() + tail.size(); } |
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163 | /// \brief Return whether the path is empty. |
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164 | bool empty() const { return head.empty() && tail.empty(); } |
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165 | |
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166 | /// \brief Reset the path to an empty one. |
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167 | void clear() { head.clear(); tail.clear(); } |
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168 | |
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169 | /// \brief The n-th arc. |
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170 | /// |
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171 | /// Gives back the n-th arc. This function runs in O(1) time. |
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172 | /// \pre \c n is in the range <tt>[0..length() - 1]</tt>. |
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173 | const Arc& nth(int n) const { |
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174 | return n < int(head.size()) ? *(head.rbegin() + n) : |
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175 | *(tail.begin() + (n - head.size())); |
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176 | } |
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177 | |
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178 | /// \brief Initialize arc iterator to point to the n-th arc |
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179 | /// |
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180 | /// \pre \c n is in the <tt>[0..length() - 1]</tt> range. |
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181 | ArcIt nthIt(int n) const { |
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182 | return ArcIt(*this, n); |
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183 | } |
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184 | |
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185 | /// \brief The first arc of the path |
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186 | const Arc& front() const { |
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187 | return head.empty() ? tail.front() : head.back(); |
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188 | } |
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189 | |
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190 | /// \brief Add a new arc before the current path |
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191 | void addFront(const Arc& arc) { |
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192 | head.push_back(arc); |
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193 | } |
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194 | |
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195 | /// \brief Erase the first arc of the path |
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196 | void eraseFront() { |
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197 | if (!head.empty()) { |
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198 | head.pop_back(); |
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199 | } else { |
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200 | head.clear(); |
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201 | int halfsize = tail.size() / 2; |
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202 | head.resize(halfsize); |
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203 | std::copy(tail.begin() + 1, tail.begin() + halfsize + 1, |
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204 | head.rbegin()); |
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205 | std::copy(tail.begin() + halfsize + 1, tail.end(), tail.begin()); |
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206 | tail.resize(tail.size() - halfsize - 1); |
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207 | } |
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208 | } |
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209 | |
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210 | /// \brief The last arc of the path |
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211 | const Arc& back() const { |
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212 | return tail.empty() ? head.front() : tail.back(); |
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213 | } |
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214 | |
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215 | /// \brief Add a new arc behind the current path |
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216 | void addBack(const Arc& arc) { |
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217 | tail.push_back(arc); |
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218 | } |
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219 | |
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220 | /// \brief Erase the last arc of the path |
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221 | void eraseBack() { |
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222 | if (!tail.empty()) { |
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223 | tail.pop_back(); |
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224 | } else { |
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225 | int halfsize = head.size() / 2; |
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226 | tail.resize(halfsize); |
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227 | std::copy(head.begin() + 1, head.begin() + halfsize + 1, |
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228 | tail.rbegin()); |
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229 | std::copy(head.begin() + halfsize + 1, head.end(), head.begin()); |
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230 | head.resize(head.size() - halfsize - 1); |
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231 | } |
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232 | } |
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233 | |
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234 | typedef True BuildTag; |
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235 | |
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236 | template <typename CPath> |
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237 | void build(const CPath& path) { |
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238 | int len = path.length(); |
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239 | tail.reserve(len); |
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240 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
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241 | tail.push_back(it); |
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242 | } |
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243 | } |
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244 | |
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245 | template <typename CPath> |
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246 | void buildRev(const CPath& path) { |
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247 | int len = path.length(); |
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248 | head.reserve(len); |
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249 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
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250 | head.push_back(it); |
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251 | } |
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252 | } |
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253 | |
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254 | protected: |
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255 | typedef std::vector<Arc> Container; |
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256 | Container head, tail; |
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257 | |
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258 | }; |
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259 | |
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260 | /// \brief A structure for representing directed paths in a digraph. |
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261 | /// |
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262 | /// A structure for representing directed path in a digraph. |
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263 | /// \tparam GR The digraph type in which the path is. |
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264 | /// |
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265 | /// In a sense, a path can be treated as a list of arcs. The |
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266 | /// LEMON path type simply stores this list. As a consequence, it |
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267 | /// cannot enumerate the nodes in the path, and the source node of |
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268 | /// a zero-length path is undefined. |
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269 | /// |
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270 | /// This implementation is a just back insertable and erasable path |
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271 | /// type. It can be indexed in O(1) time. The back insertion and |
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272 | /// erasure is amortized O(1) time. This implementation is faster |
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273 | /// than the \c Path type because it use just one vector for the |
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274 | /// arcs. |
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275 | template <typename GR> |
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276 | class SimplePath { |
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277 | public: |
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278 | |
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279 | typedef GR Digraph; |
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280 | typedef typename Digraph::Arc Arc; |
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281 | |
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282 | /// \brief Default constructor |
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283 | /// |
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284 | /// Default constructor |
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285 | SimplePath() {} |
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286 | |
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287 | /// \brief Copy constructor |
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288 | /// |
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289 | SimplePath(const SimplePath& cpath) { |
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290 | pathCopy(cpath, *this); |
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291 | } |
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292 | |
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293 | /// \brief Template copy constructor |
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294 | /// |
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295 | /// This path can be initialized with any other path type. It just |
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296 | /// makes a copy of the given path. |
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297 | template <typename CPath> |
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298 | SimplePath(const CPath& cpath) { |
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299 | pathCopy(cpath, *this); |
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300 | } |
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301 | |
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302 | /// \brief Copy assignment |
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303 | /// |
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304 | SimplePath& operator=(const SimplePath& cpath) { |
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305 | pathCopy(cpath, *this); |
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306 | return *this; |
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307 | } |
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308 | |
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309 | /// \brief Template copy assignment |
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310 | /// |
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311 | /// This path can be initialized with any other path type. It just |
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312 | /// makes a copy of the given path. |
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313 | template <typename CPath> |
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314 | SimplePath& operator=(const CPath& cpath) { |
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315 | pathCopy(cpath, *this); |
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316 | return *this; |
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317 | } |
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318 | |
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319 | /// \brief Iterator class to iterate on the arcs of the paths |
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320 | /// |
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321 | /// This class is used to iterate on the arcs of the paths |
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322 | /// |
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323 | /// Of course it converts to Digraph::Arc |
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324 | class ArcIt { |
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325 | friend class SimplePath; |
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326 | public: |
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327 | /// Default constructor |
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328 | ArcIt() {} |
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329 | /// Invalid constructor |
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330 | ArcIt(Invalid) : path(0), idx(-1) {} |
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331 | /// \brief Initializate the constructor to the first arc of path |
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332 | ArcIt(const SimplePath &_path) |
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333 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
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334 | |
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335 | private: |
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336 | |
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337 | /// Constructor with starting point |
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338 | ArcIt(const SimplePath &_path, int _idx) |
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339 | : path(&_path), idx(_idx) {} |
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340 | |
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341 | public: |
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342 | |
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343 | ///Conversion to Digraph::Arc |
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344 | operator const Arc&() const { |
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345 | return path->nth(idx); |
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346 | } |
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347 | |
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348 | /// Next arc |
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349 | ArcIt& operator++() { |
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350 | ++idx; |
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351 | if (idx >= path->length()) idx = -1; |
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352 | return *this; |
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353 | } |
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354 | |
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355 | /// Comparison operator |
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356 | bool operator==(const ArcIt& e) const { return idx==e.idx; } |
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357 | /// Comparison operator |
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358 | bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
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359 | /// Comparison operator |
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360 | bool operator<(const ArcIt& e) const { return idx<e.idx; } |
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361 | |
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362 | private: |
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363 | const SimplePath *path; |
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364 | int idx; |
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365 | }; |
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366 | |
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367 | /// \brief Gets the collection of the arcs of the path. |
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368 | /// |
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369 | /// This function can be used for iterating on the |
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370 | /// arcs of the path. It returns a wrapped |
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371 | /// ArcIt, which looks like an STL container |
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372 | /// (by having begin() and end()) which you can use in range-based |
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373 | /// for loops, STL algorithms, etc. |
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374 | /// For example you can write: |
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375 | ///\code |
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376 | /// for(auto a: p.arcs()) |
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377 | /// doSomething(a); |
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378 | ///\endcode |
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379 | LemonRangeWrapper1<ArcIt, SimplePath> arcs() const { |
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380 | return LemonRangeWrapper1<ArcIt, SimplePath>(*this); |
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381 | } |
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382 | |
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383 | |
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384 | /// \brief Length of the path. |
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385 | int length() const { return data.size(); } |
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386 | /// \brief Return true if the path is empty. |
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387 | bool empty() const { return data.empty(); } |
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388 | |
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389 | /// \brief Reset the path to an empty one. |
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390 | void clear() { data.clear(); } |
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391 | |
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392 | /// \brief The n-th arc. |
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393 | /// |
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394 | /// Gives back the n-th arc. This function runs in O(1) time. |
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395 | /// \pre \c n is in the range <tt>[0..length() - 1]</tt>. |
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396 | const Arc& nth(int n) const { |
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397 | return data[n]; |
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398 | } |
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399 | |
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400 | /// \brief Initializes arc iterator to point to the n-th arc. |
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401 | ArcIt nthIt(int n) const { |
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402 | return ArcIt(*this, n); |
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403 | } |
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404 | |
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405 | /// \brief The first arc of the path. |
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406 | const Arc& front() const { |
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407 | return data.front(); |
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408 | } |
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409 | |
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410 | /// \brief The last arc of the path. |
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411 | const Arc& back() const { |
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412 | return data.back(); |
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413 | } |
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414 | |
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415 | /// \brief Add a new arc behind the current path. |
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416 | void addBack(const Arc& arc) { |
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417 | data.push_back(arc); |
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418 | } |
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419 | |
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420 | /// \brief Erase the last arc of the path |
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421 | void eraseBack() { |
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422 | data.pop_back(); |
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423 | } |
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424 | |
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425 | typedef True BuildTag; |
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426 | |
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427 | template <typename CPath> |
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428 | void build(const CPath& path) { |
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429 | int len = path.length(); |
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430 | data.resize(len); |
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431 | int index = 0; |
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432 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
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433 | data[index] = it;; |
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434 | ++index; |
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435 | } |
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436 | } |
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437 | |
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438 | template <typename CPath> |
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439 | void buildRev(const CPath& path) { |
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440 | int len = path.length(); |
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441 | data.resize(len); |
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442 | int index = len; |
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443 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
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444 | --index; |
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445 | data[index] = it;; |
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446 | } |
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447 | } |
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448 | |
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449 | protected: |
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450 | typedef std::vector<Arc> Container; |
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451 | Container data; |
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452 | |
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453 | }; |
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454 | |
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455 | /// \brief A structure for representing directed paths in a digraph. |
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456 | /// |
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457 | /// A structure for representing directed path in a digraph. |
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458 | /// \tparam GR The digraph type in which the path is. |
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459 | /// |
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460 | /// In a sense, a path can be treated as a list of arcs. The |
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461 | /// LEMON path type simply stores this list. As a consequence, it |
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462 | /// cannot enumerate the nodes in the path, and the source node of |
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463 | /// a zero-length path is undefined. |
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464 | /// |
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465 | /// This implementation is a back and front insertable and erasable |
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466 | /// path type. It can be indexed in O(k) time, where k is the rank |
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467 | /// of the arc in the path. The length can be computed in O(n) |
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468 | /// time. The front and back insertion and erasure is O(1) time |
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469 | /// and it can be splited and spliced in O(1) time. |
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470 | template <typename GR> |
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471 | class ListPath { |
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472 | public: |
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473 | |
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474 | typedef GR Digraph; |
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475 | typedef typename Digraph::Arc Arc; |
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476 | |
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477 | protected: |
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478 | |
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479 | // the std::list<> is incompatible |
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480 | // hard to create invalid iterator |
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481 | struct Node { |
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482 | Arc arc; |
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483 | Node *next, *prev; |
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484 | }; |
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485 | |
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486 | Node *first, *last; |
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487 | |
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488 | std::allocator<Node> alloc; |
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489 | |
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490 | public: |
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491 | |
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492 | /// \brief Default constructor |
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493 | /// |
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494 | /// Default constructor |
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495 | ListPath() : first(0), last(0) {} |
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496 | |
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497 | /// \brief Copy constructor |
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498 | /// |
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499 | ListPath(const ListPath& cpath) : first(0), last(0) { |
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500 | pathCopy(cpath, *this); |
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501 | } |
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502 | |
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503 | /// \brief Template copy constructor |
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504 | /// |
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505 | /// This path can be initialized with any other path type. It just |
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506 | /// makes a copy of the given path. |
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507 | template <typename CPath> |
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508 | ListPath(const CPath& cpath) : first(0), last(0) { |
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509 | pathCopy(cpath, *this); |
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510 | } |
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511 | |
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512 | /// \brief Destructor of the path |
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513 | /// |
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514 | /// Destructor of the path |
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515 | ~ListPath() { |
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516 | clear(); |
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517 | } |
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518 | |
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519 | /// \brief Copy assignment |
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520 | /// |
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521 | ListPath& operator=(const ListPath& cpath) { |
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522 | pathCopy(cpath, *this); |
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523 | return *this; |
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524 | } |
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525 | |
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526 | /// \brief Template copy assignment |
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527 | /// |
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528 | /// This path can be initialized with any other path type. It just |
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529 | /// makes a copy of the given path. |
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530 | template <typename CPath> |
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531 | ListPath& operator=(const CPath& cpath) { |
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532 | pathCopy(cpath, *this); |
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533 | return *this; |
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534 | } |
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535 | |
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536 | /// \brief Iterator class to iterate on the arcs of the paths |
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537 | /// |
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538 | /// This class is used to iterate on the arcs of the paths |
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539 | /// |
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540 | /// Of course it converts to Digraph::Arc |
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541 | class ArcIt { |
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542 | friend class ListPath; |
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543 | public: |
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544 | /// Default constructor |
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545 | ArcIt() {} |
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546 | /// Invalid constructor |
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547 | ArcIt(Invalid) : path(0), node(0) {} |
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548 | /// \brief Initializate the constructor to the first arc of path |
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549 | ArcIt(const ListPath &_path) |
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550 | : path(&_path), node(_path.first) {} |
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551 | |
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552 | protected: |
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553 | |
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554 | ArcIt(const ListPath &_path, Node *_node) |
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555 | : path(&_path), node(_node) {} |
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556 | |
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557 | |
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558 | public: |
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559 | |
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560 | ///Conversion to Digraph::Arc |
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561 | operator const Arc&() const { |
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562 | return node->arc; |
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563 | } |
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564 | |
---|
565 | /// Next arc |
---|
566 | ArcIt& operator++() { |
---|
567 | node = node->next; |
---|
568 | return *this; |
---|
569 | } |
---|
570 | |
---|
571 | /// Comparison operator |
---|
572 | bool operator==(const ArcIt& e) const { return node==e.node; } |
---|
573 | /// Comparison operator |
---|
574 | bool operator!=(const ArcIt& e) const { return node!=e.node; } |
---|
575 | /// Comparison operator |
---|
576 | bool operator<(const ArcIt& e) const { return node<e.node; } |
---|
577 | |
---|
578 | private: |
---|
579 | const ListPath *path; |
---|
580 | Node *node; |
---|
581 | }; |
---|
582 | |
---|
583 | /// \brief Gets the collection of the arcs of the path. |
---|
584 | /// |
---|
585 | /// This function can be used for iterating on the |
---|
586 | /// arcs of the path. It returns a wrapped |
---|
587 | /// ArcIt, which looks like an STL container |
---|
588 | /// (by having begin() and end()) which you can use in range-based |
---|
589 | /// for loops, STL algorithms, etc. |
---|
590 | /// For example you can write: |
---|
591 | ///\code |
---|
592 | /// for(auto a: p.arcs()) |
---|
593 | /// doSomething(a); |
---|
594 | ///\endcode |
---|
595 | LemonRangeWrapper1<ArcIt, ListPath> arcs() const { |
---|
596 | return LemonRangeWrapper1<ArcIt, ListPath>(*this); |
---|
597 | } |
---|
598 | |
---|
599 | |
---|
600 | /// \brief The n-th arc. |
---|
601 | /// |
---|
602 | /// This function looks for the n-th arc in O(n) time. |
---|
603 | /// \pre \c n is in the range <tt>[0..length() - 1]</tt>. |
---|
604 | const Arc& nth(int n) const { |
---|
605 | Node *node = first; |
---|
606 | for (int i = 0; i < n; ++i) { |
---|
607 | node = node->next; |
---|
608 | } |
---|
609 | return node->arc; |
---|
610 | } |
---|
611 | |
---|
612 | /// \brief Initializes arc iterator to point to the n-th arc. |
---|
613 | ArcIt nthIt(int n) const { |
---|
614 | Node *node = first; |
---|
615 | for (int i = 0; i < n; ++i) { |
---|
616 | node = node->next; |
---|
617 | } |
---|
618 | return ArcIt(*this, node); |
---|
619 | } |
---|
620 | |
---|
621 | /// \brief Length of the path. |
---|
622 | int length() const { |
---|
623 | int len = 0; |
---|
624 | Node *node = first; |
---|
625 | while (node != 0) { |
---|
626 | node = node->next; |
---|
627 | ++len; |
---|
628 | } |
---|
629 | return len; |
---|
630 | } |
---|
631 | |
---|
632 | /// \brief Return true if the path is empty. |
---|
633 | bool empty() const { return first == 0; } |
---|
634 | |
---|
635 | /// \brief Reset the path to an empty one. |
---|
636 | void clear() { |
---|
637 | while (first != 0) { |
---|
638 | last = first->next; |
---|
639 | alloc.destroy(first); |
---|
640 | alloc.deallocate(first, 1); |
---|
641 | first = last; |
---|
642 | } |
---|
643 | } |
---|
644 | |
---|
645 | /// \brief The first arc of the path |
---|
646 | const Arc& front() const { |
---|
647 | return first->arc; |
---|
648 | } |
---|
649 | |
---|
650 | /// \brief Add a new arc before the current path |
---|
651 | void addFront(const Arc& arc) { |
---|
652 | Node *node = alloc.allocate(1); |
---|
653 | alloc.construct(node, Node()); |
---|
654 | node->prev = 0; |
---|
655 | node->next = first; |
---|
656 | node->arc = arc; |
---|
657 | if (first) { |
---|
658 | first->prev = node; |
---|
659 | first = node; |
---|
660 | } else { |
---|
661 | first = last = node; |
---|
662 | } |
---|
663 | } |
---|
664 | |
---|
665 | /// \brief Erase the first arc of the path |
---|
666 | void eraseFront() { |
---|
667 | Node *node = first; |
---|
668 | first = first->next; |
---|
669 | if (first) { |
---|
670 | first->prev = 0; |
---|
671 | } else { |
---|
672 | last = 0; |
---|
673 | } |
---|
674 | alloc.destroy(node); |
---|
675 | alloc.deallocate(node, 1); |
---|
676 | } |
---|
677 | |
---|
678 | /// \brief The last arc of the path. |
---|
679 | const Arc& back() const { |
---|
680 | return last->arc; |
---|
681 | } |
---|
682 | |
---|
683 | /// \brief Add a new arc behind the current path. |
---|
684 | void addBack(const Arc& arc) { |
---|
685 | Node *node = alloc.allocate(1); |
---|
686 | alloc.construct(node, Node()); |
---|
687 | node->next = 0; |
---|
688 | node->prev = last; |
---|
689 | node->arc = arc; |
---|
690 | if (last) { |
---|
691 | last->next = node; |
---|
692 | last = node; |
---|
693 | } else { |
---|
694 | last = first = node; |
---|
695 | } |
---|
696 | } |
---|
697 | |
---|
698 | /// \brief Erase the last arc of the path |
---|
699 | void eraseBack() { |
---|
700 | Node *node = last; |
---|
701 | last = last->prev; |
---|
702 | if (last) { |
---|
703 | last->next = 0; |
---|
704 | } else { |
---|
705 | first = 0; |
---|
706 | } |
---|
707 | alloc.destroy(node); |
---|
708 | alloc.deallocate(node, 1); |
---|
709 | } |
---|
710 | |
---|
711 | /// \brief Splice a path to the back of the current path. |
---|
712 | /// |
---|
713 | /// It splices \c tpath to the back of the current path and \c |
---|
714 | /// tpath becomes empty. The time complexity of this function is |
---|
715 | /// O(1). |
---|
716 | void spliceBack(ListPath& tpath) { |
---|
717 | if (first) { |
---|
718 | if (tpath.first) { |
---|
719 | last->next = tpath.first; |
---|
720 | tpath.first->prev = last; |
---|
721 | last = tpath.last; |
---|
722 | } |
---|
723 | } else { |
---|
724 | first = tpath.first; |
---|
725 | last = tpath.last; |
---|
726 | } |
---|
727 | tpath.first = tpath.last = 0; |
---|
728 | } |
---|
729 | |
---|
730 | /// \brief Splice a path to the front of the current path. |
---|
731 | /// |
---|
732 | /// It splices \c tpath before the current path and \c tpath |
---|
733 | /// becomes empty. The time complexity of this function |
---|
734 | /// is O(1). |
---|
735 | void spliceFront(ListPath& tpath) { |
---|
736 | if (first) { |
---|
737 | if (tpath.first) { |
---|
738 | first->prev = tpath.last; |
---|
739 | tpath.last->next = first; |
---|
740 | first = tpath.first; |
---|
741 | } |
---|
742 | } else { |
---|
743 | first = tpath.first; |
---|
744 | last = tpath.last; |
---|
745 | } |
---|
746 | tpath.first = tpath.last = 0; |
---|
747 | } |
---|
748 | |
---|
749 | /// \brief Splice a path into the current path. |
---|
750 | /// |
---|
751 | /// It splices the \c tpath into the current path before the |
---|
752 | /// position of \c it iterator and \c tpath becomes empty. The |
---|
753 | /// time complexity of this function is O(1). If the \c it is |
---|
754 | /// \c INVALID then it will splice behind the current path. |
---|
755 | void splice(ArcIt it, ListPath& tpath) { |
---|
756 | if (it.node) { |
---|
757 | if (tpath.first) { |
---|
758 | tpath.first->prev = it.node->prev; |
---|
759 | if (it.node->prev) { |
---|
760 | it.node->prev->next = tpath.first; |
---|
761 | } else { |
---|
762 | first = tpath.first; |
---|
763 | } |
---|
764 | it.node->prev = tpath.last; |
---|
765 | tpath.last->next = it.node; |
---|
766 | } |
---|
767 | } else { |
---|
768 | if (first) { |
---|
769 | if (tpath.first) { |
---|
770 | last->next = tpath.first; |
---|
771 | tpath.first->prev = last; |
---|
772 | last = tpath.last; |
---|
773 | } |
---|
774 | } else { |
---|
775 | first = tpath.first; |
---|
776 | last = tpath.last; |
---|
777 | } |
---|
778 | } |
---|
779 | tpath.first = tpath.last = 0; |
---|
780 | } |
---|
781 | |
---|
782 | /// \brief Split the current path. |
---|
783 | /// |
---|
784 | /// It splits the current path into two parts. The part before |
---|
785 | /// the iterator \c it will remain in the current path and the part |
---|
786 | /// starting with |
---|
787 | /// \c it will put into \c tpath. If \c tpath have arcs |
---|
788 | /// before the operation they are removed first. The time |
---|
789 | /// complexity of this function is O(1) plus the time of emtying |
---|
790 | /// \c tpath. If \c it is \c INVALID then it just clears \c tpath |
---|
791 | void split(ArcIt it, ListPath& tpath) { |
---|
792 | tpath.clear(); |
---|
793 | if (it.node) { |
---|
794 | tpath.first = it.node; |
---|
795 | tpath.last = last; |
---|
796 | if (it.node->prev) { |
---|
797 | last = it.node->prev; |
---|
798 | last->next = 0; |
---|
799 | } else { |
---|
800 | first = last = 0; |
---|
801 | } |
---|
802 | it.node->prev = 0; |
---|
803 | } |
---|
804 | } |
---|
805 | |
---|
806 | |
---|
807 | typedef True BuildTag; |
---|
808 | |
---|
809 | template <typename CPath> |
---|
810 | void build(const CPath& path) { |
---|
811 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
---|
812 | addBack(it); |
---|
813 | } |
---|
814 | } |
---|
815 | |
---|
816 | template <typename CPath> |
---|
817 | void buildRev(const CPath& path) { |
---|
818 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
---|
819 | addFront(it); |
---|
820 | } |
---|
821 | } |
---|
822 | |
---|
823 | }; |
---|
824 | |
---|
825 | /// \brief A structure for representing directed paths in a digraph. |
---|
826 | /// |
---|
827 | /// A structure for representing directed path in a digraph. |
---|
828 | /// \tparam GR The digraph type in which the path is. |
---|
829 | /// |
---|
830 | /// In a sense, a path can be treated as a list of arcs. The |
---|
831 | /// LEMON path type simply stores this list. As a consequence, it |
---|
832 | /// cannot enumerate the nodes in the path, and the source node of |
---|
833 | /// a zero-length path is undefined. |
---|
834 | /// |
---|
835 | /// This implementation is completly static, i.e. it can be copy constucted |
---|
836 | /// or copy assigned from another path, but otherwise it cannot be |
---|
837 | /// modified. |
---|
838 | /// |
---|
839 | /// Being the most memory-efficient path type in LEMON, it is |
---|
840 | /// intented to be used when you want to store a large number of paths. |
---|
841 | template <typename GR> |
---|
842 | class StaticPath { |
---|
843 | public: |
---|
844 | |
---|
845 | typedef GR Digraph; |
---|
846 | typedef typename Digraph::Arc Arc; |
---|
847 | |
---|
848 | /// \brief Default constructor |
---|
849 | /// |
---|
850 | /// Default constructor |
---|
851 | StaticPath() : len(0), _arcs(0) {} |
---|
852 | |
---|
853 | /// \brief Copy constructor |
---|
854 | /// |
---|
855 | StaticPath(const StaticPath& cpath) : _arcs(0) { |
---|
856 | pathCopy(cpath, *this); |
---|
857 | } |
---|
858 | |
---|
859 | /// \brief Template copy constructor |
---|
860 | /// |
---|
861 | /// This path can be initialized from any other path type. |
---|
862 | template <typename CPath> |
---|
863 | StaticPath(const CPath& cpath) : _arcs(0) { |
---|
864 | pathCopy(cpath, *this); |
---|
865 | } |
---|
866 | |
---|
867 | /// \brief Destructor of the path |
---|
868 | /// |
---|
869 | /// Destructor of the path |
---|
870 | ~StaticPath() { |
---|
871 | if (_arcs) delete[] _arcs; |
---|
872 | } |
---|
873 | |
---|
874 | /// \brief Copy assignment |
---|
875 | /// |
---|
876 | StaticPath& operator=(const StaticPath& cpath) { |
---|
877 | pathCopy(cpath, *this); |
---|
878 | return *this; |
---|
879 | } |
---|
880 | |
---|
881 | /// \brief Template copy assignment |
---|
882 | /// |
---|
883 | /// This path can be made equal to any other path type. It simply |
---|
884 | /// makes a copy of the given path. |
---|
885 | template <typename CPath> |
---|
886 | StaticPath& operator=(const CPath& cpath) { |
---|
887 | pathCopy(cpath, *this); |
---|
888 | return *this; |
---|
889 | } |
---|
890 | |
---|
891 | /// \brief Iterator class to iterate on the arcs of the paths |
---|
892 | /// |
---|
893 | /// This class is used to iterate on the arcs of the paths |
---|
894 | /// |
---|
895 | /// Of course it converts to Digraph::Arc |
---|
896 | class ArcIt { |
---|
897 | friend class StaticPath; |
---|
898 | public: |
---|
899 | /// Default constructor |
---|
900 | ArcIt() {} |
---|
901 | /// Invalid constructor |
---|
902 | ArcIt(Invalid) : path(0), idx(-1) {} |
---|
903 | /// Initializate the constructor to the first arc of path |
---|
904 | ArcIt(const StaticPath &_path) |
---|
905 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
---|
906 | |
---|
907 | private: |
---|
908 | |
---|
909 | /// Constructor with starting point |
---|
910 | ArcIt(const StaticPath &_path, int _idx) |
---|
911 | : idx(_idx), path(&_path) {} |
---|
912 | |
---|
913 | public: |
---|
914 | |
---|
915 | ///Conversion to Digraph::Arc |
---|
916 | operator const Arc&() const { |
---|
917 | return path->nth(idx); |
---|
918 | } |
---|
919 | |
---|
920 | /// Next arc |
---|
921 | ArcIt& operator++() { |
---|
922 | ++idx; |
---|
923 | if (idx >= path->length()) idx = -1; |
---|
924 | return *this; |
---|
925 | } |
---|
926 | |
---|
927 | /// Comparison operator |
---|
928 | bool operator==(const ArcIt& e) const { return idx==e.idx; } |
---|
929 | /// Comparison operator |
---|
930 | bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
---|
931 | /// Comparison operator |
---|
932 | bool operator<(const ArcIt& e) const { return idx<e.idx; } |
---|
933 | |
---|
934 | private: |
---|
935 | const StaticPath *path; |
---|
936 | int idx; |
---|
937 | }; |
---|
938 | |
---|
939 | /// \brief Gets the collection of the arcs of the path. |
---|
940 | /// |
---|
941 | /// This function can be used for iterating on the |
---|
942 | /// arcs of the path. It returns a wrapped |
---|
943 | /// ArcIt, which looks like an STL container |
---|
944 | /// (by having begin() and end()) which you can use in range-based |
---|
945 | /// for loops, STL algorithms, etc. |
---|
946 | /// For example you can write: |
---|
947 | ///\code |
---|
948 | /// for(auto a: p.arcs()) |
---|
949 | /// doSomething(a); |
---|
950 | ///\endcode |
---|
951 | LemonRangeWrapper1<ArcIt, StaticPath> arcs() const { |
---|
952 | return LemonRangeWrapper1<ArcIt, StaticPath>(*this); |
---|
953 | } |
---|
954 | |
---|
955 | |
---|
956 | /// \brief The n-th arc. |
---|
957 | /// |
---|
958 | /// Gives back the n-th arc. This function runs in O(1) time. |
---|
959 | /// \pre \c n is in the range <tt>[0..length() - 1]</tt>. |
---|
960 | const Arc& nth(int n) const { |
---|
961 | return _arcs[n]; |
---|
962 | } |
---|
963 | |
---|
964 | /// \brief The arc iterator pointing to the n-th arc. |
---|
965 | ArcIt nthIt(int n) const { |
---|
966 | return ArcIt(*this, n); |
---|
967 | } |
---|
968 | |
---|
969 | /// \brief The length of the path. |
---|
970 | int length() const { return len; } |
---|
971 | |
---|
972 | /// \brief Return true when the path is empty. |
---|
973 | int empty() const { return len == 0; } |
---|
974 | |
---|
975 | /// \brief Reset the path to an empty one. |
---|
976 | void clear() { |
---|
977 | len = 0; |
---|
978 | if (_arcs) delete[] _arcs; |
---|
979 | _arcs = 0; |
---|
980 | } |
---|
981 | |
---|
982 | /// \brief The first arc of the path. |
---|
983 | const Arc& front() const { |
---|
984 | return _arcs[0]; |
---|
985 | } |
---|
986 | |
---|
987 | /// \brief The last arc of the path. |
---|
988 | const Arc& back() const { |
---|
989 | return _arcs[len - 1]; |
---|
990 | } |
---|
991 | |
---|
992 | |
---|
993 | typedef True BuildTag; |
---|
994 | |
---|
995 | template <typename CPath> |
---|
996 | void build(const CPath& path) { |
---|
997 | len = path.length(); |
---|
998 | _arcs = new Arc[len]; |
---|
999 | int index = 0; |
---|
1000 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
---|
1001 | _arcs[index] = it; |
---|
1002 | ++index; |
---|
1003 | } |
---|
1004 | } |
---|
1005 | |
---|
1006 | template <typename CPath> |
---|
1007 | void buildRev(const CPath& path) { |
---|
1008 | len = path.length(); |
---|
1009 | _arcs = new Arc[len]; |
---|
1010 | int index = len; |
---|
1011 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
---|
1012 | --index; |
---|
1013 | _arcs[index] = it; |
---|
1014 | } |
---|
1015 | } |
---|
1016 | |
---|
1017 | private: |
---|
1018 | int len; |
---|
1019 | Arc* _arcs; |
---|
1020 | }; |
---|
1021 | |
---|
1022 | /////////////////////////////////////////////////////////////////////// |
---|
1023 | // Additional utilities |
---|
1024 | /////////////////////////////////////////////////////////////////////// |
---|
1025 | |
---|
1026 | namespace _path_bits { |
---|
1027 | |
---|
1028 | template <typename Path, typename Enable = void> |
---|
1029 | struct RevPathTagIndicator { |
---|
1030 | static const bool value = false; |
---|
1031 | }; |
---|
1032 | |
---|
1033 | template <typename Path> |
---|
1034 | struct RevPathTagIndicator< |
---|
1035 | Path, |
---|
1036 | typename enable_if<typename Path::RevPathTag, void>::type |
---|
1037 | > { |
---|
1038 | static const bool value = true; |
---|
1039 | }; |
---|
1040 | |
---|
1041 | template <typename Path, typename Enable = void> |
---|
1042 | struct BuildTagIndicator { |
---|
1043 | static const bool value = false; |
---|
1044 | }; |
---|
1045 | |
---|
1046 | template <typename Path> |
---|
1047 | struct BuildTagIndicator< |
---|
1048 | Path, |
---|
1049 | typename enable_if<typename Path::BuildTag, void>::type |
---|
1050 | > { |
---|
1051 | static const bool value = true; |
---|
1052 | }; |
---|
1053 | |
---|
1054 | template <typename From, typename To, |
---|
1055 | bool buildEnable = BuildTagIndicator<To>::value> |
---|
1056 | struct PathCopySelectorForward { |
---|
1057 | static void copy(const From& from, To& to) { |
---|
1058 | to.clear(); |
---|
1059 | for (typename From::ArcIt it(from); it != INVALID; ++it) { |
---|
1060 | to.addBack(it); |
---|
1061 | } |
---|
1062 | } |
---|
1063 | }; |
---|
1064 | |
---|
1065 | template <typename From, typename To> |
---|
1066 | struct PathCopySelectorForward<From, To, true> { |
---|
1067 | static void copy(const From& from, To& to) { |
---|
1068 | to.clear(); |
---|
1069 | to.build(from); |
---|
1070 | } |
---|
1071 | }; |
---|
1072 | |
---|
1073 | template <typename From, typename To, |
---|
1074 | bool buildEnable = BuildTagIndicator<To>::value> |
---|
1075 | struct PathCopySelectorBackward { |
---|
1076 | static void copy(const From& from, To& to) { |
---|
1077 | to.clear(); |
---|
1078 | for (typename From::RevArcIt it(from); it != INVALID; ++it) { |
---|
1079 | to.addFront(it); |
---|
1080 | } |
---|
1081 | } |
---|
1082 | }; |
---|
1083 | |
---|
1084 | template <typename From, typename To> |
---|
1085 | struct PathCopySelectorBackward<From, To, true> { |
---|
1086 | static void copy(const From& from, To& to) { |
---|
1087 | to.clear(); |
---|
1088 | to.buildRev(from); |
---|
1089 | } |
---|
1090 | }; |
---|
1091 | |
---|
1092 | |
---|
1093 | template <typename From, typename To, |
---|
1094 | bool revEnable = RevPathTagIndicator<From>::value> |
---|
1095 | struct PathCopySelector { |
---|
1096 | static void copy(const From& from, To& to) { |
---|
1097 | PathCopySelectorForward<From, To>::copy(from, to); |
---|
1098 | } |
---|
1099 | }; |
---|
1100 | |
---|
1101 | template <typename From, typename To> |
---|
1102 | struct PathCopySelector<From, To, true> { |
---|
1103 | static void copy(const From& from, To& to) { |
---|
1104 | PathCopySelectorBackward<From, To>::copy(from, to); |
---|
1105 | } |
---|
1106 | }; |
---|
1107 | |
---|
1108 | } |
---|
1109 | |
---|
1110 | |
---|
1111 | /// \brief Make a copy of a path. |
---|
1112 | /// |
---|
1113 | /// This function makes a copy of a path. |
---|
1114 | template <typename From, typename To> |
---|
1115 | void pathCopy(const From& from, To& to) { |
---|
1116 | checkConcept<concepts::PathDumper<typename From::Digraph>, From>(); |
---|
1117 | _path_bits::PathCopySelector<From, To>::copy(from, to); |
---|
1118 | } |
---|
1119 | |
---|
1120 | /// \brief Deprecated version of \ref pathCopy(). |
---|
1121 | /// |
---|
1122 | /// Deprecated version of \ref pathCopy() (only for reverse compatibility). |
---|
1123 | template <typename To, typename From> |
---|
1124 | void copyPath(To& to, const From& from) { |
---|
1125 | pathCopy(from, to); |
---|
1126 | } |
---|
1127 | |
---|
1128 | /// \brief Check the consistency of a path. |
---|
1129 | /// |
---|
1130 | /// This function checks that the target of each arc is the same |
---|
1131 | /// as the source of the next one. |
---|
1132 | /// |
---|
1133 | template <typename Digraph, typename Path> |
---|
1134 | bool checkPath(const Digraph& digraph, const Path& path) { |
---|
1135 | typename Path::ArcIt it(path); |
---|
1136 | if (it == INVALID) return true; |
---|
1137 | typename Digraph::Node node = digraph.target(it); |
---|
1138 | ++it; |
---|
1139 | while (it != INVALID) { |
---|
1140 | if (digraph.source(it) != node) return false; |
---|
1141 | node = digraph.target(it); |
---|
1142 | ++it; |
---|
1143 | } |
---|
1144 | return true; |
---|
1145 | } |
---|
1146 | |
---|
1147 | /// \brief The source of a path |
---|
1148 | /// |
---|
1149 | /// This function returns the source node of the given path. |
---|
1150 | /// If the path is empty, then it returns \c INVALID. |
---|
1151 | template <typename Digraph, typename Path> |
---|
1152 | typename Digraph::Node pathSource(const Digraph& digraph, const Path& path) { |
---|
1153 | return path.empty() ? INVALID : digraph.source(path.front()); |
---|
1154 | } |
---|
1155 | |
---|
1156 | /// \brief The target of a path |
---|
1157 | /// |
---|
1158 | /// This function returns the target node of the given path. |
---|
1159 | /// If the path is empty, then it returns \c INVALID. |
---|
1160 | template <typename Digraph, typename Path> |
---|
1161 | typename Digraph::Node pathTarget(const Digraph& digraph, const Path& path) { |
---|
1162 | return path.empty() ? INVALID : digraph.target(path.back()); |
---|
1163 | } |
---|
1164 | |
---|
1165 | /// \brief Class for iterating through the nodes of a path |
---|
1166 | /// |
---|
1167 | /// Class for iterating through the nodes of a path. |
---|
1168 | /// |
---|
1169 | /// In a sense, a path can be treated as a list of arcs. The |
---|
1170 | /// LEMON path type simply stores this list. As a consequence, it |
---|
1171 | /// cannot enumerate the nodes in the path, and the source node of |
---|
1172 | /// a zero-length path is undefined. |
---|
1173 | /// |
---|
1174 | /// However, this class implements a node iterator for path structures. |
---|
1175 | /// To provide this feature, the underlying digraph should be passed to |
---|
1176 | /// the constructor of the iterator. |
---|
1177 | template <typename Path> |
---|
1178 | class PathNodeIt { |
---|
1179 | private: |
---|
1180 | const typename Path::Digraph *_digraph; |
---|
1181 | typename Path::ArcIt _it; |
---|
1182 | typename Path::Digraph::Node _nd; |
---|
1183 | |
---|
1184 | public: |
---|
1185 | |
---|
1186 | typedef typename Path::Digraph Digraph; |
---|
1187 | typedef typename Digraph::Node Node; |
---|
1188 | |
---|
1189 | /// Default constructor |
---|
1190 | PathNodeIt() {} |
---|
1191 | /// Invalid constructor |
---|
1192 | PathNodeIt(Invalid) |
---|
1193 | : _digraph(0), _it(INVALID), _nd(INVALID) {} |
---|
1194 | /// Constructor |
---|
1195 | PathNodeIt(const Digraph& digraph, const Path& path) |
---|
1196 | : _digraph(&digraph), _it(path) { |
---|
1197 | _nd = (_it != INVALID ? _digraph->source(_it) : INVALID); |
---|
1198 | } |
---|
1199 | /// Constructor |
---|
1200 | PathNodeIt(const Digraph& digraph, const Path& path, const Node& src) |
---|
1201 | : _digraph(&digraph), _it(path), _nd(src) {} |
---|
1202 | |
---|
1203 | ///Conversion to Digraph::Node |
---|
1204 | operator Node() const { |
---|
1205 | return _nd; |
---|
1206 | } |
---|
1207 | |
---|
1208 | /// Next node |
---|
1209 | PathNodeIt& operator++() { |
---|
1210 | if (_it == INVALID) _nd = INVALID; |
---|
1211 | else { |
---|
1212 | _nd = _digraph->target(_it); |
---|
1213 | ++_it; |
---|
1214 | } |
---|
1215 | return *this; |
---|
1216 | } |
---|
1217 | |
---|
1218 | /// Comparison operator |
---|
1219 | bool operator==(const PathNodeIt& n) const { |
---|
1220 | return _it == n._it && _nd == n._nd; |
---|
1221 | } |
---|
1222 | /// Comparison operator |
---|
1223 | bool operator!=(const PathNodeIt& n) const { |
---|
1224 | return _it != n._it || _nd != n._nd; |
---|
1225 | } |
---|
1226 | /// Comparison operator |
---|
1227 | bool operator<(const PathNodeIt& n) const { |
---|
1228 | return (_it < n._it && _nd != INVALID); |
---|
1229 | } |
---|
1230 | |
---|
1231 | }; |
---|
1232 | |
---|
1233 | /// \brief Gets the collection of the nodes of the path. |
---|
1234 | /// |
---|
1235 | /// This function can be used for iterating on the |
---|
1236 | /// nodes of the path. It returns a wrapped |
---|
1237 | /// PathNodeIt, which looks like an STL container |
---|
1238 | /// (by having begin() and end()) which you can use in range-based |
---|
1239 | /// for loops, STL algorithms, etc. |
---|
1240 | /// For example you can write: |
---|
1241 | ///\code |
---|
1242 | /// for(auto u: pathNodes(g,p)) |
---|
1243 | /// doSomething(u); |
---|
1244 | ///\endcode |
---|
1245 | template<typename Path> |
---|
1246 | LemonRangeWrapper2<PathNodeIt<Path>, typename Path::Digraph, Path> |
---|
1247 | pathNodes(const typename Path::Digraph &g, const Path &p) { |
---|
1248 | return |
---|
1249 | LemonRangeWrapper2<PathNodeIt<Path>, typename Path::Digraph, Path>(g,p); |
---|
1250 | } |
---|
1251 | |
---|
1252 | ///@} |
---|
1253 | |
---|
1254 | } // namespace lemon |
---|
1255 | |
---|
1256 | #endif // LEMON_PATH_H |
---|