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