1 | /* -*- C++ -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library |
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4 | * |
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5 | * Copyright (C) 2003-2008 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | ///\ingroup paths |
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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 | |
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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/path_utils.h> |
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31 | #include <lemon/error.h> |
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32 | #include <lemon/bits/invalid.h> |
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33 | |
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34 | namespace lemon { |
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35 | |
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36 | /// \addtogroup paths |
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37 | /// @{ |
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38 | |
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39 | |
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40 | /// \brief A structure for representing directed paths in a graph. |
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41 | /// |
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42 | /// A structure for representing directed path in a graph. |
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43 | /// \param Graph The graph type in which the path is. |
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44 | /// |
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45 | /// In a sense, the path can be treated as a list of edges. The |
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46 | /// lemon path type stores just this list. As a consequence it |
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47 | /// cannot enumerate the nodes in the path and the zero length paths |
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48 | /// cannot store the source. |
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49 | /// |
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50 | /// This implementation is a back and front insertable and erasable |
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51 | /// path type. It can be indexed in O(1) time. The front and back |
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52 | /// insertion and erasure is amortized O(1) time. The |
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53 | /// impelementation is based on two opposite organized vectors. |
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54 | template <typename _Graph> |
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55 | class Path { |
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56 | public: |
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57 | |
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58 | typedef _Graph Graph; |
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59 | typedef typename Graph::Edge Edge; |
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60 | |
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61 | /// \brief Default constructor |
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62 | /// |
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63 | /// Default constructor |
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64 | Path() {} |
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65 | |
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66 | /// \brief Template copy constructor |
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67 | /// |
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68 | /// This path can be initialized with any other path type. It just |
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69 | /// makes a copy of the given path. |
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70 | template <typename CPath> |
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71 | Path(const CPath& cpath) { |
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72 | copyPath(*this, cpath); |
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73 | } |
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74 | |
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75 | /// \brief Template copy assignment |
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76 | /// |
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77 | /// This path can be initialized with any other path type. It just |
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78 | /// makes a copy of the given path. |
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79 | template <typename CPath> |
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80 | Path& operator=(const CPath& cpath) { |
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81 | copyPath(*this, cpath); |
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82 | return *this; |
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83 | } |
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84 | |
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85 | /// \brief Lemon style iterator for path edges |
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86 | /// |
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87 | /// This class is used to iterate on the edges of the paths. |
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88 | class EdgeIt { |
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89 | friend class Path; |
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90 | public: |
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91 | /// \brief Default constructor |
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92 | EdgeIt() {} |
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93 | /// \brief Invalid constructor |
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94 | EdgeIt(Invalid) : path(0), idx(-1) {} |
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95 | /// \brief Initializate the constructor to the first edge of path |
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96 | EdgeIt(const Path &_path) |
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97 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
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98 | |
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99 | private: |
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100 | |
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101 | EdgeIt(const Path &_path, int _idx) |
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102 | : path(&_path), idx(_idx) {} |
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103 | |
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104 | public: |
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105 | |
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106 | /// \brief Conversion to Edge |
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107 | operator const Edge&() const { |
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108 | return path->nth(idx); |
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109 | } |
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110 | |
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111 | /// \brief Next edge |
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112 | EdgeIt& operator++() { |
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113 | ++idx; |
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114 | if (idx >= path->length()) idx = -1; |
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115 | return *this; |
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116 | } |
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117 | |
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118 | /// \brief Comparison operator |
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119 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
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120 | /// \brief Comparison operator |
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121 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
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122 | /// \brief Comparison operator |
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123 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
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124 | |
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125 | private: |
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126 | const Path *path; |
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127 | int idx; |
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128 | }; |
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129 | |
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130 | /// \brief Length of the path. |
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131 | int length() const { return head.size() + tail.size(); } |
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132 | /// \brief Returns whether the path is empty. |
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133 | bool empty() const { return head.empty() && tail.empty(); } |
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134 | |
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135 | /// \brief Resets the path to an empty path. |
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136 | void clear() { head.clear(); tail.clear(); } |
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137 | |
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138 | /// \brief Gives back the nth edge. |
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139 | /// |
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140 | /// \pre n is in the [0..length() - 1] range |
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141 | const Edge& nth(int n) const { |
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142 | return n < int(head.size()) ? *(head.rbegin() + n) : |
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143 | *(tail.begin() + (n - head.size())); |
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144 | } |
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145 | |
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146 | /// \brief Initializes edge iterator to point to the nth edge |
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147 | /// |
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148 | /// \pre n is in the [0..length() - 1] range |
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149 | EdgeIt nthIt(int n) const { |
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150 | return EdgeIt(*this, n); |
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151 | } |
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152 | |
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153 | /// \brief Gives back the first edge of the path |
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154 | const Edge& front() const { |
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155 | return head.empty() ? tail.front() : head.back(); |
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156 | } |
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157 | |
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158 | /// \brief Add a new edge before the current path |
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159 | void addFront(const Edge& edge) { |
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160 | head.push_back(edge); |
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161 | } |
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162 | |
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163 | /// \brief Erase the first edge of the path |
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164 | void eraseFront() { |
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165 | if (!head.empty()) { |
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166 | head.pop_back(); |
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167 | } else { |
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168 | head.clear(); |
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169 | int halfsize = tail.size() / 2; |
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170 | head.resize(halfsize); |
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171 | std::copy(tail.begin() + 1, tail.begin() + halfsize + 1, |
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172 | head.rbegin()); |
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173 | std::copy(tail.begin() + halfsize + 1, tail.end(), tail.begin()); |
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174 | tail.resize(tail.size() - halfsize - 1); |
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175 | } |
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176 | } |
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177 | |
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178 | /// \brief Gives back the last edge of the path |
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179 | const Edge& back() const { |
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180 | return tail.empty() ? head.front() : tail.back(); |
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181 | } |
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182 | |
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183 | /// \brief Add a new edge behind the current path |
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184 | void addBack(const Edge& edge) { |
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185 | tail.push_back(edge); |
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186 | } |
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187 | |
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188 | /// \brief Erase the last edge of the path |
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189 | void eraseBack() { |
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190 | if (!tail.empty()) { |
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191 | tail.pop_back(); |
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192 | } else { |
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193 | int halfsize = head.size() / 2; |
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194 | tail.resize(halfsize); |
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195 | std::copy(head.begin() + 1, head.begin() + halfsize + 1, |
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196 | tail.rbegin()); |
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197 | std::copy(head.begin() + halfsize + 1, head.end(), head.begin()); |
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198 | head.resize(head.size() - halfsize - 1); |
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199 | } |
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200 | } |
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201 | |
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202 | |
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203 | |
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204 | typedef True BuildTag; |
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205 | |
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206 | template <typename CPath> |
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207 | void build(const CPath& path) { |
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208 | int len = path.length(); |
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209 | tail.reserve(len); |
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210 | for (typename CPath::EdgeIt it(path); it != INVALID; ++it) { |
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211 | tail.push_back(it); |
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212 | } |
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213 | } |
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214 | |
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215 | template <typename CPath> |
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216 | void buildRev(const CPath& path) { |
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217 | int len = path.length(); |
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218 | head.reserve(len); |
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219 | for (typename CPath::RevEdgeIt it(path); it != INVALID; ++it) { |
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220 | head.push_back(it); |
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221 | } |
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222 | } |
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223 | |
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224 | protected: |
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225 | typedef std::vector<Edge> Container; |
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226 | Container head, tail; |
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227 | |
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228 | }; |
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229 | |
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230 | /// \brief A structure for representing directed paths in a graph. |
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231 | /// |
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232 | /// A structure for representing directed path in a graph. |
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233 | /// \param Graph The graph type in which the path is. |
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234 | /// |
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235 | /// In a sense, the path can be treated as a list of edges. The |
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236 | /// lemon path type stores just this list. As a consequence it |
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237 | /// cannot enumerate the nodes in the path and the zero length paths |
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238 | /// cannot store the source. |
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239 | /// |
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240 | /// This implementation is a just back insertable and erasable path |
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241 | /// type. It can be indexed in O(1) time. The back insertion and |
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242 | /// erasure is amortized O(1) time. This implementation is faster |
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243 | /// then the \c Path type because it use just one vector for the |
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244 | /// edges. |
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245 | template <typename _Graph> |
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246 | class SimplePath { |
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247 | public: |
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248 | |
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249 | typedef _Graph Graph; |
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250 | typedef typename Graph::Edge Edge; |
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251 | |
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252 | /// \brief Default constructor |
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253 | /// |
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254 | /// Default constructor |
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255 | SimplePath() {} |
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256 | |
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257 | /// \brief Template copy constructor |
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258 | /// |
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259 | /// This path can be initialized with any other path type. It just |
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260 | /// makes a copy of the given path. |
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261 | template <typename CPath> |
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262 | SimplePath(const CPath& cpath) { |
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263 | copyPath(*this, cpath); |
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264 | } |
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265 | |
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266 | /// \brief Template copy assignment |
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267 | /// |
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268 | /// This path can be initialized with any other path type. It just |
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269 | /// makes a copy of the given path. |
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270 | template <typename CPath> |
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271 | SimplePath& operator=(const CPath& cpath) { |
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272 | copyPath(*this, cpath); |
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273 | return *this; |
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274 | } |
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275 | |
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276 | /// \brief Iterator class to iterate on the edges of the paths |
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277 | /// |
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278 | /// This class is used to iterate on the edges of the paths |
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279 | /// |
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280 | /// Of course it converts to Graph::Edge |
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281 | class EdgeIt { |
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282 | friend class SimplePath; |
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283 | public: |
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284 | /// Default constructor |
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285 | EdgeIt() {} |
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286 | /// Invalid constructor |
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287 | EdgeIt(Invalid) : path(0), idx(-1) {} |
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288 | /// \brief Initializate the constructor to the first edge of path |
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289 | EdgeIt(const SimplePath &_path) |
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290 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
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291 | |
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292 | private: |
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293 | |
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294 | /// Constructor with starting point |
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295 | EdgeIt(const SimplePath &_path, int _idx) |
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296 | : idx(_idx), path(&_path) {} |
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297 | |
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298 | public: |
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299 | |
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300 | ///Conversion to Graph::Edge |
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301 | operator const Edge&() const { |
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302 | return path->nth(idx); |
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303 | } |
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304 | |
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305 | /// Next edge |
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306 | EdgeIt& operator++() { |
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307 | ++idx; |
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308 | if (idx >= path->length()) idx = -1; |
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309 | return *this; |
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310 | } |
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311 | |
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312 | /// Comparison operator |
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313 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
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314 | /// Comparison operator |
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315 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
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316 | /// Comparison operator |
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317 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
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318 | |
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319 | private: |
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320 | const SimplePath *path; |
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321 | int idx; |
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322 | }; |
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323 | |
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324 | /// \brief Length of the path. |
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325 | int length() const { return data.size(); } |
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326 | /// \brief Returns whether the path is empty. |
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327 | bool empty() const { return data.empty(); } |
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328 | |
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329 | /// \brief Resets the path to an empty path. |
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330 | void clear() { data.clear(); } |
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331 | |
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332 | /// \brief Gives back the nth edge. |
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333 | /// |
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334 | /// \pre n is in the [0..length() - 1] range |
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335 | const Edge& nth(int n) const { |
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336 | return data[n]; |
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337 | } |
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338 | |
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339 | /// \brief Initializes edge iterator to point to the nth edge. |
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340 | EdgeIt nthIt(int n) const { |
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341 | return EdgeIt(*this, n); |
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342 | } |
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343 | |
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344 | /// \brief Gives back the first edge of the path. |
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345 | const Edge& front() const { |
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346 | return data.front(); |
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347 | } |
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348 | |
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349 | /// \brief Gives back the last edge of the path. |
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350 | const Edge& back() const { |
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351 | return data.back(); |
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352 | } |
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353 | |
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354 | /// \brief Add a new edge behind the current path. |
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355 | void addBack(const Edge& edge) { |
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356 | data.push_back(edge); |
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357 | } |
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358 | |
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359 | /// \brief Erase the last edge of the path |
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360 | void eraseBack() { |
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361 | data.pop_back(); |
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362 | } |
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363 | |
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364 | typedef True BuildTag; |
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365 | |
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366 | template <typename CPath> |
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367 | void build(const CPath& path) { |
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368 | int len = path.length(); |
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369 | data.resize(len); |
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370 | int index = 0; |
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371 | for (typename CPath::EdgeIt it(path); it != INVALID; ++it) { |
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372 | data[index] = it;; |
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373 | ++index; |
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374 | } |
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375 | } |
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376 | |
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377 | template <typename CPath> |
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378 | void buildRev(const CPath& path) { |
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379 | int len = path.length(); |
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380 | data.resize(len); |
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381 | int index = len; |
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382 | for (typename CPath::RevEdgeIt it(path); it != INVALID; ++it) { |
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383 | --index; |
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384 | data[index] = it;; |
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385 | } |
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386 | } |
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387 | |
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388 | protected: |
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389 | typedef std::vector<Edge> Container; |
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390 | Container data; |
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391 | |
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392 | }; |
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393 | |
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394 | /// \brief A structure for representing directed paths in a graph. |
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395 | /// |
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396 | /// A structure for representing directed path in a graph. |
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397 | /// \param Graph The graph type in which the path is. |
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398 | /// |
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399 | /// In a sense, the path can be treated as a list of edges. The |
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400 | /// lemon path type stores just this list. As a consequence it |
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401 | /// cannot enumerate the nodes in the path and the zero length paths |
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402 | /// cannot store the source. |
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403 | /// |
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404 | /// This implementation is a back and front insertable and erasable |
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405 | /// path type. It can be indexed in O(k) time, where k is the rank |
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406 | /// of the edge in the path. The length can be computed in O(n) |
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407 | /// time. The front and back insertion and erasure is O(1) time |
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408 | /// and it can be splited and spliced in O(1) time. |
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409 | template <typename _Graph> |
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410 | class ListPath { |
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411 | public: |
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412 | |
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413 | typedef _Graph Graph; |
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414 | typedef typename Graph::Edge Edge; |
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415 | |
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416 | protected: |
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417 | |
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418 | // the std::list<> is incompatible |
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419 | // hard to create invalid iterator |
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420 | struct Node { |
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421 | Edge edge; |
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422 | Node *next, *prev; |
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423 | }; |
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424 | |
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425 | Node *first, *last; |
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426 | |
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427 | std::allocator<Node> alloc; |
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428 | |
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429 | public: |
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430 | |
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431 | /// \brief Default constructor |
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432 | /// |
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433 | /// Default constructor |
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434 | ListPath() : first(0), last(0) {} |
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435 | |
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436 | /// \brief Template copy constructor |
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437 | /// |
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438 | /// This path can be initialized with any other path type. It just |
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439 | /// makes a copy of the given path. |
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440 | template <typename CPath> |
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441 | ListPath(const CPath& cpath) : first(0), last(0) { |
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442 | copyPath(*this, cpath); |
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443 | } |
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444 | |
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445 | /// \brief Destructor of the path |
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446 | /// |
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447 | /// Destructor of the path |
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448 | ~ListPath() { |
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449 | clear(); |
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450 | } |
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451 | |
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452 | /// \brief Template copy assignment |
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453 | /// |
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454 | /// This path can be initialized with any other path type. It just |
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455 | /// makes a copy of the given path. |
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456 | template <typename CPath> |
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457 | ListPath& operator=(const CPath& cpath) { |
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458 | copyPath(*this, cpath); |
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459 | return *this; |
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460 | } |
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461 | |
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462 | /// \brief Iterator class to iterate on the edges of the paths |
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463 | /// |
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464 | /// This class is used to iterate on the edges of the paths |
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465 | /// |
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466 | /// Of course it converts to Graph::Edge |
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467 | class EdgeIt { |
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468 | friend class ListPath; |
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469 | public: |
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470 | /// Default constructor |
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471 | EdgeIt() {} |
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472 | /// Invalid constructor |
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473 | EdgeIt(Invalid) : path(0), node(0) {} |
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474 | /// \brief Initializate the constructor to the first edge of path |
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475 | EdgeIt(const ListPath &_path) |
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476 | : path(&_path), node(_path.first) {} |
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477 | |
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478 | protected: |
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479 | |
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480 | EdgeIt(const ListPath &_path, Node *_node) |
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481 | : path(&_path), node(_node) {} |
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482 | |
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483 | |
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484 | public: |
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485 | |
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486 | ///Conversion to Graph::Edge |
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487 | operator const Edge&() const { |
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488 | return node->edge; |
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489 | } |
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490 | |
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491 | /// Next edge |
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492 | EdgeIt& operator++() { |
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493 | node = node->next; |
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494 | return *this; |
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495 | } |
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496 | |
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497 | /// Comparison operator |
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498 | bool operator==(const EdgeIt& e) const { return node==e.node; } |
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499 | /// Comparison operator |
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500 | bool operator!=(const EdgeIt& e) const { return node!=e.node; } |
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501 | /// Comparison operator |
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502 | bool operator<(const EdgeIt& e) const { return node<e.node; } |
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503 | |
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504 | private: |
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505 | const ListPath *path; |
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506 | Node *node; |
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507 | }; |
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508 | |
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509 | /// \brief Gives back the nth edge. |
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510 | /// |
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511 | /// Gives back the nth edge in O(n) time. |
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512 | /// \pre n is in the [0..length() - 1] range |
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513 | const Edge& nth(int n) const { |
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514 | Node *node = first; |
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515 | for (int i = 0; i < n; ++i) { |
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516 | node = node->next; |
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517 | } |
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518 | return node->edge; |
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519 | } |
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520 | |
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521 | /// \brief Initializes edge iterator to point to the nth edge. |
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522 | EdgeIt nthIt(int n) const { |
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523 | Node *node = first; |
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524 | for (int i = 0; i < n; ++i) { |
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525 | node = node->next; |
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526 | } |
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527 | return EdgeIt(*this, node); |
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528 | } |
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529 | |
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530 | /// \brief Length of the path. |
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531 | int length() const { |
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532 | int len = 0; |
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533 | Node *node = first; |
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534 | while (node != 0) { |
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535 | node = node->next; |
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536 | ++len; |
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537 | } |
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538 | return len; |
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539 | } |
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540 | |
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541 | /// \brief Returns whether the path is empty. |
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542 | bool empty() const { return first == 0; } |
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543 | |
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544 | /// \brief Resets the path to an empty path. |
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545 | void clear() { |
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546 | while (first != 0) { |
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547 | last = first->next; |
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548 | alloc.destroy(first); |
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549 | alloc.deallocate(first, 1); |
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550 | first = last; |
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551 | } |
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552 | } |
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553 | |
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554 | /// \brief Gives back the first edge of the path |
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555 | const Edge& front() const { |
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556 | return first->edge; |
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557 | } |
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558 | |
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559 | /// \brief Add a new edge before the current path |
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560 | void addFront(const Edge& edge) { |
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561 | Node *node = alloc.allocate(1); |
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562 | alloc.construct(node, Node()); |
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563 | node->prev = 0; |
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564 | node->next = first; |
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565 | node->edge = edge; |
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566 | if (first) { |
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567 | first->prev = node; |
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568 | first = node; |
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569 | } else { |
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570 | first = last = node; |
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571 | } |
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572 | } |
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573 | |
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574 | /// \brief Erase the first edge of the path |
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575 | void eraseFront() { |
---|
576 | Node *node = first; |
---|
577 | first = first->next; |
---|
578 | if (first) { |
---|
579 | first->prev = 0; |
---|
580 | } else { |
---|
581 | last = 0; |
---|
582 | } |
---|
583 | alloc.destroy(node); |
---|
584 | alloc.deallocate(node, 1); |
---|
585 | } |
---|
586 | |
---|
587 | /// \brief Gives back the last edge of the path. |
---|
588 | const Edge& back() const { |
---|
589 | return last->edge; |
---|
590 | } |
---|
591 | |
---|
592 | /// \brief Add a new edge behind the current path. |
---|
593 | void addBack(const Edge& edge) { |
---|
594 | Node *node = alloc.allocate(1); |
---|
595 | alloc.construct(node, Node()); |
---|
596 | node->next = 0; |
---|
597 | node->prev = last; |
---|
598 | node->edge = edge; |
---|
599 | if (last) { |
---|
600 | last->next = node; |
---|
601 | last = node; |
---|
602 | } else { |
---|
603 | last = first = node; |
---|
604 | } |
---|
605 | } |
---|
606 | |
---|
607 | /// \brief Erase the last edge of the path |
---|
608 | void eraseBack() { |
---|
609 | Node *node = last; |
---|
610 | last = last->prev; |
---|
611 | if (last) { |
---|
612 | last->next = 0; |
---|
613 | } else { |
---|
614 | first = 0; |
---|
615 | } |
---|
616 | alloc.destroy(node); |
---|
617 | alloc.deallocate(node, 1); |
---|
618 | } |
---|
619 | |
---|
620 | /// \brief Splicing the given path to the current path. |
---|
621 | /// |
---|
622 | /// It splices the \c tpath to the back of the current path and \c |
---|
623 | /// tpath becomes empty. The time complexity of this function is |
---|
624 | /// O(1). |
---|
625 | void spliceBack(ListPath& tpath) { |
---|
626 | if (first) { |
---|
627 | if (tpath.first) { |
---|
628 | last->next = tpath.first; |
---|
629 | tpath.first->prev = last; |
---|
630 | last = tpath.last; |
---|
631 | } |
---|
632 | } else { |
---|
633 | first = tpath.first; |
---|
634 | last = tpath.last; |
---|
635 | } |
---|
636 | tpath.first = tpath.last = 0; |
---|
637 | } |
---|
638 | |
---|
639 | /// \brief Splicing the given path to the current path. |
---|
640 | /// |
---|
641 | /// It splices the \c tpath before the current path and \c tpath |
---|
642 | /// becomes empty. The time complexity of this function |
---|
643 | /// is O(1). |
---|
644 | void spliceFront(ListPath& tpath) { |
---|
645 | if (first) { |
---|
646 | if (tpath.first) { |
---|
647 | first->prev = tpath.last; |
---|
648 | tpath.last->next = first; |
---|
649 | first = tpath.first; |
---|
650 | } |
---|
651 | } else { |
---|
652 | first = tpath.first; |
---|
653 | last = tpath.last; |
---|
654 | } |
---|
655 | tpath.first = tpath.last = 0; |
---|
656 | } |
---|
657 | |
---|
658 | /// \brief Splicing the given path into the current path. |
---|
659 | /// |
---|
660 | /// It splices the \c tpath into the current path before the |
---|
661 | /// position of \c it iterator and \c tpath becomes empty. The |
---|
662 | /// time complexity of this function is O(1). If the \c it is \c |
---|
663 | /// INVALID then it will splice behind the current path. |
---|
664 | void splice(EdgeIt it, ListPath& tpath) { |
---|
665 | if (it.node) { |
---|
666 | if (tpath.first) { |
---|
667 | tpath.first->prev = it.node->prev; |
---|
668 | if (it.node->prev) { |
---|
669 | it.node->prev->next = tpath.first; |
---|
670 | } else { |
---|
671 | first = tpath.first; |
---|
672 | } |
---|
673 | it.node->prev = tpath.last; |
---|
674 | tpath.last->next = it.node; |
---|
675 | } |
---|
676 | } else { |
---|
677 | if (first) { |
---|
678 | if (tpath.first) { |
---|
679 | last->next = tpath.first; |
---|
680 | tpath.first->prev = last; |
---|
681 | last = tpath.last; |
---|
682 | } |
---|
683 | } else { |
---|
684 | first = tpath.first; |
---|
685 | last = tpath.last; |
---|
686 | } |
---|
687 | } |
---|
688 | tpath.first = tpath.last = 0; |
---|
689 | } |
---|
690 | |
---|
691 | /// \brief Spliting the current path. |
---|
692 | /// |
---|
693 | /// It splits the current path into two parts. The part before \c |
---|
694 | /// it iterator will remain in the current path and the part from |
---|
695 | /// the it will put into the \c tpath. If the \c tpath had edges |
---|
696 | /// before the operation they will be removed first. The time |
---|
697 | /// complexity of this function is O(1) plus the clearing of \c |
---|
698 | /// tpath. If the \c it is \c INVALID then it just clears \c |
---|
699 | /// tpath. |
---|
700 | void split(EdgeIt it, ListPath& tpath) { |
---|
701 | tpath.clear(); |
---|
702 | if (it.node) { |
---|
703 | tpath.first = it.node; |
---|
704 | tpath.last = last; |
---|
705 | if (it.node->prev) { |
---|
706 | last = it.node->prev; |
---|
707 | last->next = 0; |
---|
708 | } else { |
---|
709 | first = last = 0; |
---|
710 | } |
---|
711 | it.node->prev = 0; |
---|
712 | } |
---|
713 | } |
---|
714 | |
---|
715 | |
---|
716 | typedef True BuildTag; |
---|
717 | |
---|
718 | template <typename CPath> |
---|
719 | void build(const CPath& path) { |
---|
720 | for (typename CPath::EdgeIt it(path); it != INVALID; ++it) { |
---|
721 | addBack(it); |
---|
722 | } |
---|
723 | } |
---|
724 | |
---|
725 | template <typename CPath> |
---|
726 | void buildRev(const CPath& path) { |
---|
727 | for (typename CPath::RevEdgeIt it(path); it != INVALID; ++it) { |
---|
728 | addFront(it); |
---|
729 | } |
---|
730 | } |
---|
731 | |
---|
732 | }; |
---|
733 | |
---|
734 | /// \brief A structure for representing directed paths in a graph. |
---|
735 | /// |
---|
736 | /// A structure for representing directed path in a graph. |
---|
737 | /// \param Graph The graph type in which the path is. |
---|
738 | /// |
---|
739 | /// In a sense, the path can be treated as a list of edges. The |
---|
740 | /// lemon path type stores just this list. As a consequence it |
---|
741 | /// cannot enumerate the nodes in the path and the zero length paths |
---|
742 | /// cannot store the source. |
---|
743 | /// |
---|
744 | /// This implementation is completly static, so it cannot be |
---|
745 | /// modified exclude the assign an other path. It is intented to be |
---|
746 | /// used when you want to store a large number of paths because it is |
---|
747 | /// the most memory efficient path type in the lemon. |
---|
748 | template <typename _Graph> |
---|
749 | class StaticPath { |
---|
750 | public: |
---|
751 | |
---|
752 | typedef _Graph Graph; |
---|
753 | typedef typename Graph::Edge Edge; |
---|
754 | |
---|
755 | /// \brief Default constructor |
---|
756 | /// |
---|
757 | /// Default constructor |
---|
758 | StaticPath() : len(0), edges(0) {} |
---|
759 | |
---|
760 | /// \brief Template copy constructor |
---|
761 | /// |
---|
762 | /// This path can be initialized with any other path type. It just |
---|
763 | /// makes a copy of the given path. |
---|
764 | template <typename CPath> |
---|
765 | StaticPath(const CPath& cpath) : edges(0) { |
---|
766 | copyPath(*this, cpath); |
---|
767 | } |
---|
768 | |
---|
769 | /// \brief Destructor of the path |
---|
770 | /// |
---|
771 | /// Destructor of the path |
---|
772 | ~StaticPath() { |
---|
773 | if (edges) delete[] edges; |
---|
774 | } |
---|
775 | |
---|
776 | /// \brief Template copy assignment |
---|
777 | /// |
---|
778 | /// This path can be initialized with any other path type. It just |
---|
779 | /// makes a copy of the given path. |
---|
780 | template <typename CPath> |
---|
781 | StaticPath& operator=(const CPath& cpath) { |
---|
782 | copyPath(*this, cpath); |
---|
783 | return *this; |
---|
784 | } |
---|
785 | |
---|
786 | /// \brief Iterator class to iterate on the edges of the paths |
---|
787 | /// |
---|
788 | /// This class is used to iterate on the edges of the paths |
---|
789 | /// |
---|
790 | /// Of course it converts to Graph::Edge |
---|
791 | class EdgeIt { |
---|
792 | friend class StaticPath; |
---|
793 | public: |
---|
794 | /// Default constructor |
---|
795 | EdgeIt() {} |
---|
796 | /// Invalid constructor |
---|
797 | EdgeIt(Invalid) : path(0), idx(-1) {} |
---|
798 | /// Initializate the constructor to the first edge of path |
---|
799 | EdgeIt(const StaticPath &_path) |
---|
800 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
---|
801 | |
---|
802 | private: |
---|
803 | |
---|
804 | /// Constructor with starting point |
---|
805 | EdgeIt(const StaticPath &_path, int _idx) |
---|
806 | : idx(_idx), path(&_path) {} |
---|
807 | |
---|
808 | public: |
---|
809 | |
---|
810 | ///Conversion to Graph::Edge |
---|
811 | operator const Edge&() const { |
---|
812 | return path->nth(idx); |
---|
813 | } |
---|
814 | |
---|
815 | /// Next edge |
---|
816 | EdgeIt& operator++() { |
---|
817 | ++idx; |
---|
818 | if (idx >= path->length()) idx = -1; |
---|
819 | return *this; |
---|
820 | } |
---|
821 | |
---|
822 | /// Comparison operator |
---|
823 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
---|
824 | /// Comparison operator |
---|
825 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
---|
826 | /// Comparison operator |
---|
827 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
---|
828 | |
---|
829 | private: |
---|
830 | const StaticPath *path; |
---|
831 | int idx; |
---|
832 | }; |
---|
833 | |
---|
834 | /// \brief Gives back the nth edge. |
---|
835 | /// |
---|
836 | /// \pre n is in the [0..length() - 1] range |
---|
837 | const Edge& nth(int n) const { |
---|
838 | return edges[n]; |
---|
839 | } |
---|
840 | |
---|
841 | /// \brief Initializes edge iterator to point to the nth edge. |
---|
842 | EdgeIt nthIt(int n) const { |
---|
843 | return EdgeIt(*this, n); |
---|
844 | } |
---|
845 | |
---|
846 | /// \brief Gives back the length of the path. |
---|
847 | int length() const { return len; } |
---|
848 | |
---|
849 | /// \brief Returns true when the path is empty. |
---|
850 | int empty() const { return len == 0; } |
---|
851 | |
---|
852 | /// \break Erase all edge in the graph. |
---|
853 | void clear() { |
---|
854 | len = 0; |
---|
855 | if (edges) delete[] edges; |
---|
856 | edges = 0; |
---|
857 | } |
---|
858 | |
---|
859 | /// \brief Gives back the first edge of the path. |
---|
860 | const Edge& front() const { |
---|
861 | return edges[0]; |
---|
862 | } |
---|
863 | |
---|
864 | /// \brief Gives back the last edge of the path. |
---|
865 | const Edge& back() const { |
---|
866 | return edges[len - 1]; |
---|
867 | } |
---|
868 | |
---|
869 | |
---|
870 | typedef True BuildTag; |
---|
871 | |
---|
872 | template <typename CPath> |
---|
873 | void build(const CPath& path) { |
---|
874 | len = path.length(); |
---|
875 | edges = new Edge[len]; |
---|
876 | int index = 0; |
---|
877 | for (typename CPath::EdgeIt it(path); it != INVALID; ++it) { |
---|
878 | edges[index] = it; |
---|
879 | ++index; |
---|
880 | } |
---|
881 | } |
---|
882 | |
---|
883 | template <typename CPath> |
---|
884 | void buildRev(const CPath& path) { |
---|
885 | len = path.length(); |
---|
886 | edges = new Edge[len]; |
---|
887 | int index = len; |
---|
888 | for (typename CPath::RevEdgeIt it(path); it != INVALID; ++it) { |
---|
889 | --index; |
---|
890 | edges[index] = it; |
---|
891 | } |
---|
892 | } |
---|
893 | |
---|
894 | private: |
---|
895 | int len; |
---|
896 | Edge* edges; |
---|
897 | }; |
---|
898 | |
---|
899 | ///@} |
---|
900 | |
---|
901 | } // namespace lemon |
---|
902 | |
---|
903 | #endif // LEMON_PATH_H |
---|