1 | // -*- c++ -*- // |
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2 | |
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3 | ///ingroup datas |
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4 | ///\file |
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5 | ///\brief Class for representing paths in graphs. |
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6 | |
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7 | #ifndef HUGO_PATH_H |
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8 | #define HUGO_PATH_H |
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9 | |
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10 | #include <deque> |
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11 | #include <vector> |
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12 | #include <algorithm> |
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13 | |
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14 | #include <invalid.h> |
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15 | |
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16 | namespace hugo { |
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17 | |
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18 | /// \addtogroup datas |
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19 | /// @{ |
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20 | |
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21 | ///A container for directed paths |
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22 | |
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23 | ///\param Graph The graph type in which the path is. |
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24 | /// |
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25 | ///In a sense, the path can be treated as a graph, for is has \c NodeIt |
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26 | ///and \c EdgeIt with the same usage. These types converts to the \c Node |
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27 | ///and \c Edge of the original graph. |
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28 | ///\todo How to clear a path? |
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29 | ///\todo Clarify the consistency checks to do. |
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30 | template<typename Graph> |
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31 | class DirPath { |
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32 | public: |
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33 | typedef typename Graph::Edge GraphEdge; |
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34 | typedef typename Graph::Node GraphNode; |
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35 | class NodeIt; |
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36 | class EdgeIt; |
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37 | |
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38 | protected: |
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39 | const Graph *gr; |
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40 | typedef std::vector<GraphEdge> Container; |
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41 | Container edges; |
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42 | |
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43 | public: |
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44 | |
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45 | /// Constructor |
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46 | |
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47 | /// \param _G The graph in which the path is. |
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48 | /// |
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49 | DirPath(const Graph &_G) : gr(&_G) {} |
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50 | |
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51 | /// Subpath defined by two nodes. |
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52 | /// \warning It is an error if the two edges are not in order! |
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53 | DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b); |
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54 | /// Subpath defined by two edges. Contains edges in [a,b) |
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55 | /// \warning It is an error if the two edges are not in order! |
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56 | DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b); |
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57 | |
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58 | size_t length() const { return edges.size(); } |
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59 | bool empty() const { return edges.empty(); } |
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60 | GraphNode from() const { |
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61 | return empty() ? INVALID : gr->tail(edges[0]); |
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62 | } |
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63 | GraphNode to() const { |
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64 | return empty() ? INVALID : gr->head(edges[length()-1]); |
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65 | } |
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66 | |
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67 | template<typename It> |
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68 | It& first(It &i) const { return i=It(*this); } |
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69 | |
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70 | template<typename It> |
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71 | It& nth(It &i, int n) const { return i=It(*this, n); } |
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72 | |
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73 | template<typename It> |
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74 | bool valid(const It &i) const { return i.valid(); } |
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75 | |
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76 | template<typename It> |
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77 | It& next(It &e) const { return ++e; } |
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78 | |
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79 | /// \todo ! |
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80 | NodeIt head(const EdgeIt& e) const; |
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81 | NodeIt tail(const EdgeIt& e) const; |
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82 | |
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83 | |
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84 | /*** Iterator classes ***/ |
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85 | class EdgeIt { |
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86 | friend class DirPath; |
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87 | |
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88 | int idx; |
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89 | const DirPath *p; |
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90 | public: |
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91 | EdgeIt() {} |
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92 | EdgeIt(Invalid) : idx(-1), p(0) {} |
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93 | EdgeIt(const DirPath &_p, int _idx = 0) : |
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94 | idx(_idx), p(&_p) { validate(); } |
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95 | |
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96 | bool valid() const { return idx!=-1; } |
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97 | |
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98 | operator GraphEdge () const { |
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99 | return valid() ? p->edges[idx] : INVALID; |
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100 | } |
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101 | EdgeIt& operator++() { ++idx; validate(); return *this; } |
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102 | |
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103 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
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104 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
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105 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
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106 | |
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107 | private: |
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108 | // FIXME: comparison between signed and unsigned... |
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109 | // Jo ez igy? Vagy esetleg legyen a length() int? |
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110 | void validate() { if( size_t(idx) >= p->length() ) idx=-1; } |
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111 | }; |
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112 | |
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113 | class NodeIt { |
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114 | friend class DirPath; |
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115 | |
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116 | int idx; |
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117 | const DirPath *p; |
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118 | public: |
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119 | NodeIt() {} |
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120 | NodeIt(Invalid) : idx(-1), p(0) {} |
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121 | NodeIt(const DirPath &_p, int _idx = 0) : |
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122 | idx(_idx), p(&_p) { validate(); } |
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123 | |
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124 | bool valid() const { return idx!=-1; } |
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125 | |
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126 | operator const GraphEdge& () const { |
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127 | if(idx >= p->length()) |
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128 | return p->to(); |
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129 | else if(idx >= 0) |
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130 | return p->gr->tail(p->edges[idx]); |
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131 | else |
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132 | return INVALID; |
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133 | } |
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134 | NodeIt& operator++() { ++idx; validate(); return *this; } |
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135 | |
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136 | bool operator==(const NodeIt& e) const { return idx==e.idx; } |
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137 | bool operator!=(const NodeIt& e) const { return idx!=e.idx; } |
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138 | bool operator<(const NodeIt& e) const { return idx<e.idx; } |
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139 | |
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140 | private: |
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141 | void validate() { if( size_t(idx) > p->length() ) idx=-1; } |
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142 | }; |
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143 | |
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144 | friend class Builder; |
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145 | |
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146 | ///Class to build paths |
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147 | |
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148 | ///\ingroup datas |
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149 | ///This class is used to build new paths. |
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150 | ///You can push new edges to the front and to the back of the path in |
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151 | ///arbitrary order the you can commit these changes to the graph. |
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152 | ///\todo We must clarify when the path will be in "transitional" state. |
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153 | class Builder { |
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154 | DirPath &P; |
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155 | Container d; |
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156 | |
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157 | public: |
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158 | ///Constructor |
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159 | |
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160 | ///\param _P the path you want to build. |
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161 | /// |
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162 | Builder(DirPath &_P) : P(_P) {} |
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163 | |
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164 | ///Set the first node of the path. |
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165 | |
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166 | ///Set the first node of the path. |
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167 | ///If the path is empty, this must be call before any call of |
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168 | ///\ref pushFront() or \ref pushBack() |
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169 | void setFirst(const GraphNode &) { } |
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170 | |
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171 | ///Push a new edge to the front of the path |
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172 | |
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173 | ///Push a new edge to the front of the path. |
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174 | ///\sa setFirst() |
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175 | bool pushFront(const GraphEdge& e) { |
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176 | if( empty() || P.gr->head(e)==from() ) { |
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177 | d.push_back(e); |
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178 | return true; |
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179 | } |
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180 | return false; |
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181 | } |
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182 | ///Push a new edge to the back of the path |
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183 | |
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184 | ///Push a new edge to the back of the path. |
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185 | ///\sa setFirst() |
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186 | bool pushBack(const GraphEdge& e) { |
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187 | if( empty() || P.gr->tail(e)==to() ) { |
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188 | P.edges.push_back(e); |
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189 | return true; |
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190 | } |
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191 | return false; |
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192 | } |
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193 | |
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194 | ///Commit the changes to the path. |
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195 | void commit() { |
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196 | if( !d.empty() ) { |
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197 | P.edges.insert(P.edges.begin(), d.rbegin(), d.rend()); |
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198 | d.clear(); |
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199 | } |
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200 | } |
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201 | |
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202 | ///Desctuctor |
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203 | |
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204 | ///The desctuctor. |
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205 | ///It commit also commit the changes. |
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206 | ///\todo Is this what we want? |
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207 | ~Builder() { commit(); } |
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208 | |
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209 | // FIXME: Hmm, pontosan hogy is kene ezt csinalni? |
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210 | // Hogy kenyelmes egy ilyet hasznalni? |
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211 | void reserve(size_t r) { |
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212 | d.reserve(r); |
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213 | P.edges.reserve(P.length()+r); |
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214 | } |
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215 | |
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216 | private: |
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217 | bool empty() { return d.empty() && P.empty(); } |
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218 | |
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219 | GraphNode from() const { |
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220 | if( ! d.empty() ) |
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221 | return P.gr->tail(d[d.size()-1]); |
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222 | else if( ! P.empty() ) |
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223 | return P.gr->tail(P.edges[0]); |
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224 | else |
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225 | return INVALID; |
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226 | } |
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227 | GraphNode to() const { |
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228 | if( ! P.empty() ) |
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229 | return P.gr->head(P.edges[P.length()-1]); |
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230 | else if( ! d.empty() ) |
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231 | return P.gr->head(d[0]); |
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232 | else |
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233 | return INVALID; |
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234 | } |
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235 | |
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236 | }; |
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237 | |
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238 | }; |
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239 | |
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240 | |
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241 | |
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242 | |
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243 | |
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244 | |
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245 | |
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246 | |
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247 | |
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248 | |
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249 | /**********************************************************************/ |
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250 | |
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251 | |
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252 | /* Ennek az allocatorosdinak sokkal jobban utana kene nezni a hasznalata |
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253 | elott. Eleg bonyinak nez ki, ahogyan azokat az STL-ben hasznaljak. */ |
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254 | |
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255 | template<typename Graph> |
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256 | class DynamicPath { |
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257 | |
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258 | public: |
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259 | typedef typename Graph::Edge GraphEdge; |
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260 | typedef typename Graph::Node GraphNode; |
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261 | class NodeIt; |
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262 | class EdgeIt; |
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263 | |
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264 | protected: |
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265 | Graph& G; |
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266 | // FIXME: ehelyett eleg lenne tarolni ket boolt: a ket szelso el |
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267 | // iranyitasat: |
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268 | GraphNode _first, _last; |
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269 | typedef std::deque<GraphEdge> Container; |
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270 | Container edges; |
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271 | |
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272 | public: |
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273 | |
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274 | DynamicPath(Graph &_G) : G(_G), _first(INVALID), _last(INVALID) {} |
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275 | |
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276 | /// Subpath defined by two nodes. |
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277 | /// Nodes may be in reversed order, then |
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278 | /// we contstruct the reversed path. |
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279 | DynamicPath(const DynamicPath &P, const NodeIt &a, const NodeIt &b); |
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280 | /// Subpath defined by two edges. Contains edges in [a,b) |
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281 | /// It is an error if the two edges are not in order! |
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282 | DynamicPath(const DynamicPath &P, const EdgeIt &a, const EdgeIt &b); |
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283 | |
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284 | size_t length() const { return edges.size(); } |
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285 | GraphNode from() const { return _first; } |
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286 | GraphNode to() const { return _last; } |
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287 | |
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288 | NodeIt& first(NodeIt &n) const { return nth(n, 0); } |
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289 | EdgeIt& first(EdgeIt &e) const { return nth(e, 0); } |
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290 | template<typename It> |
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291 | It first() const { |
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292 | It e; |
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293 | first(e); |
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294 | return e; |
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295 | } |
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296 | |
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297 | NodeIt& nth(NodeIt &, size_t) const; |
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298 | EdgeIt& nth(EdgeIt &, size_t) const; |
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299 | template<typename It> |
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300 | It nth(size_t n) const { |
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301 | It e; |
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302 | nth(e, n); |
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303 | return e; |
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304 | } |
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305 | |
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306 | bool valid(const NodeIt &n) const { return n.idx <= length(); } |
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307 | bool valid(const EdgeIt &e) const { return e.it < edges.end(); } |
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308 | |
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309 | bool isForward(const EdgeIt &e) const { return e.forw; } |
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310 | |
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311 | /// index of a node on the path. Returns length+2 for the invalid NodeIt |
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312 | int index(const NodeIt &n) const { return n.idx; } |
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313 | /// index of an edge on the path. Returns length+1 for the invalid EdgeIt |
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314 | int index(const EdgeIt &e) const { return e.it - edges.begin(); } |
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315 | |
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316 | EdgeIt& next(EdgeIt &e) const; |
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317 | NodeIt& next(NodeIt &n) const; |
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318 | template <typename It> |
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319 | It getNext(It it) const { |
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320 | It tmp(it); return next(tmp); |
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321 | } |
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322 | |
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323 | // A path is constructed using the following four functions. |
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324 | // They return false if the requested operation is inconsistent |
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325 | // with the path constructed so far. |
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326 | // If your path has only one edge you MUST set either "from" or "to"! |
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327 | // So you probably SHOULD call it in any case to be safe (and check the |
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328 | // returned value to check if your path is consistent with your idea). |
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329 | bool pushFront(const GraphEdge &e); |
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330 | bool pushBack(const GraphEdge &e); |
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331 | bool setFrom(const GraphNode &n); |
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332 | bool setTo(const GraphNode &n); |
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333 | |
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334 | // WARNING: these two functions return the head/tail of an edge with |
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335 | // respect to the direction of the path! |
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336 | // So G.head(P.graphEdge(e)) == P.graphNode(P.head(e)) holds only if |
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337 | // P.forward(e) is true (or the edge is a loop)! |
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338 | NodeIt head(const EdgeIt& e) const; |
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339 | NodeIt tail(const EdgeIt& e) const; |
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340 | |
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341 | // FIXME: ezeknek valami jobb nev kellene!!! |
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342 | GraphEdge graphEdge(const EdgeIt& e) const; |
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343 | GraphNode graphNode(const NodeIt& n) const; |
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344 | |
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345 | |
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346 | /*** Iterator classes ***/ |
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347 | class EdgeIt { |
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348 | friend class DynamicPath; |
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349 | |
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350 | typename Container::const_iterator it; |
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351 | bool forw; |
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352 | public: |
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353 | // FIXME: jarna neki ilyen is... |
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354 | // EdgeIt(Invalid); |
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355 | |
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356 | bool forward() const { return forw; } |
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357 | |
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358 | bool operator==(const EdgeIt& e) const { return it==e.it; } |
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359 | bool operator!=(const EdgeIt& e) const { return it!=e.it; } |
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360 | bool operator<(const EdgeIt& e) const { return it<e.it; } |
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361 | }; |
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362 | |
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363 | class NodeIt { |
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364 | friend class DynamicPath; |
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365 | |
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366 | size_t idx; |
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367 | bool tail; // Is this node the tail of the edge with same idx? |
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368 | |
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369 | public: |
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370 | // FIXME: jarna neki ilyen is... |
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371 | // NodeIt(Invalid); |
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372 | |
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373 | bool operator==(const NodeIt& n) const { return idx==n.idx; } |
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374 | bool operator!=(const NodeIt& n) const { return idx!=n.idx; } |
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375 | bool operator<(const NodeIt& n) const { return idx<n.idx; } |
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376 | }; |
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377 | |
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378 | private: |
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379 | bool edgeIncident(const GraphEdge &e, const GraphNode &a, |
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380 | GraphNode &b); |
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381 | bool connectTwoEdges(const GraphEdge &e, const GraphEdge &f); |
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382 | }; |
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383 | |
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384 | template<typename Gr> |
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385 | typename DynamicPath<Gr>::EdgeIt& |
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386 | DynamicPath<Gr>::next(DynamicPath::EdgeIt &e) const { |
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387 | if( e.it == edges.end() ) |
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388 | return e; |
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389 | |
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390 | GraphNode common_node = ( e.forw ? G.head(*e.it) : G.tail(*e.it) ); |
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391 | ++e.it; |
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392 | |
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393 | // Invalid edgeit is always forward :) |
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394 | if( e.it == edges.end() ) { |
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395 | e.forw = true; |
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396 | return e; |
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397 | } |
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398 | |
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399 | e.forw = ( G.tail(*e.it) == common_node ); |
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400 | return e; |
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401 | } |
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402 | |
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403 | template<typename Gr> |
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404 | typename DynamicPath<Gr>::NodeIt& DynamicPath<Gr>::next(NodeIt &n) const { |
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405 | if( n.idx >= length() ) { |
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406 | // FIXME: invalid |
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407 | n.idx = length()+1; |
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408 | return n; |
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409 | } |
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410 | |
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411 | |
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412 | GraphNode next_node = ( n.tail ? G.head(edges[n.idx]) : |
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413 | G.tail(edges[n.idx]) ); |
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414 | ++n.idx; |
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415 | if( n.idx < length() ) { |
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416 | n.tail = ( next_node == G.tail(edges[n.idx]) ); |
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417 | } |
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418 | else { |
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419 | n.tail = true; |
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420 | } |
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421 | |
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422 | return n; |
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423 | } |
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424 | |
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425 | template<typename Gr> |
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426 | bool DynamicPath<Gr>::edgeIncident(const GraphEdge &e, const GraphNode &a, |
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427 | GraphNode &b) { |
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428 | if( G.tail(e) == a ) { |
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429 | b=G.head(e); |
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430 | return true; |
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431 | } |
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432 | if( G.head(e) == a ) { |
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433 | b=G.tail(e); |
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434 | return true; |
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435 | } |
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436 | return false; |
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437 | } |
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438 | |
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439 | template<typename Gr> |
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440 | bool DynamicPath<Gr>::connectTwoEdges(const GraphEdge &e, |
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441 | const GraphEdge &f) { |
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442 | if( edgeIncident(f, G.tail(e), _last) ) { |
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443 | _first = G.head(e); |
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444 | return true; |
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445 | } |
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446 | if( edgeIncident(f, G.head(e), _last) ) { |
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447 | _first = G.tail(e); |
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448 | return true; |
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449 | } |
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450 | return false; |
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451 | } |
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452 | |
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453 | template<typename Gr> |
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454 | bool DynamicPath<Gr>::pushFront(const GraphEdge &e) { |
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455 | if( G.valid(_first) ) { |
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456 | if( edgeIncident(e, _first, _first) ) { |
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457 | edges.push_front(e); |
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458 | return true; |
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459 | } |
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460 | else |
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461 | return false; |
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462 | } |
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463 | else if( length() < 1 || connectTwoEdges(e, edges[0]) ) { |
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464 | edges.push_front(e); |
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465 | return true; |
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466 | } |
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467 | else |
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468 | return false; |
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469 | } |
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470 | |
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471 | template<typename Gr> |
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472 | bool DynamicPath<Gr>::pushBack(const GraphEdge &e) { |
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473 | if( G.valid(_last) ) { |
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474 | if( edgeIncident(e, _last, _last) ) { |
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475 | edges.push_back(e); |
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476 | return true; |
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477 | } |
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478 | else |
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479 | return false; |
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480 | } |
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481 | else if( length() < 1 || connectTwoEdges(edges[0], e) ) { |
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482 | edges.push_back(e); |
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483 | return true; |
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484 | } |
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485 | else |
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486 | return false; |
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487 | } |
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488 | |
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489 | |
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490 | template<typename Gr> |
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491 | bool DynamicPath<Gr>::setFrom(const GraphNode &n) { |
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492 | if( G.valid(_first) ) { |
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493 | return _first == n; |
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494 | } |
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495 | else { |
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496 | if( length() > 0) { |
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497 | if( edgeIncident(edges[0], n, _last) ) { |
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498 | _first = n; |
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499 | return true; |
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500 | } |
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501 | else return false; |
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502 | } |
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503 | else { |
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504 | _first = _last = n; |
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505 | return true; |
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506 | } |
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507 | } |
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508 | } |
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509 | |
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510 | template<typename Gr> |
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511 | bool DynamicPath<Gr>::setTo(const GraphNode &n) { |
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512 | if( G.valid(_last) ) { |
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513 | return _last == n; |
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514 | } |
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515 | else { |
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516 | if( length() > 0) { |
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517 | if( edgeIncident(edges[0], n, _first) ) { |
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518 | _last = n; |
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519 | return true; |
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520 | } |
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521 | else return false; |
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522 | } |
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523 | else { |
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524 | _first = _last = n; |
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525 | return true; |
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526 | } |
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527 | } |
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528 | } |
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529 | |
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530 | |
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531 | template<typename Gr> |
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532 | typename DynamicPath<Gr>::NodeIt |
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533 | DynamicPath<Gr>::tail(const EdgeIt& e) const { |
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534 | NodeIt n; |
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535 | |
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536 | if( e.it == edges.end() ) { |
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537 | // FIXME: invalid-> invalid |
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538 | n.idx = length() + 1; |
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539 | n.tail = true; |
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540 | return n; |
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541 | } |
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542 | |
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543 | n.idx = e.it-edges.begin(); |
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544 | n.tail = e.forw; |
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545 | return n; |
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546 | } |
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547 | |
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548 | template<typename Gr> |
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549 | typename DynamicPath<Gr>::NodeIt |
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550 | DynamicPath<Gr>::head(const EdgeIt& e) const { |
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551 | if( e.it == edges.end()-1 ) { |
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552 | return _last; |
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553 | } |
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554 | |
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555 | EdgeIt next_edge = e; |
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556 | next(next_edge); |
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557 | return tail(next_edge); |
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558 | } |
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559 | |
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560 | template<typename Gr> |
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561 | typename DynamicPath<Gr>::GraphEdge |
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562 | DynamicPath<Gr>::graphEdge(const EdgeIt& e) const { |
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563 | if( e.it != edges.end() ) { |
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564 | return *e.it; |
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565 | } |
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566 | else { |
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567 | return INVALID; |
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568 | } |
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569 | } |
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570 | |
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571 | template<typename Gr> |
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572 | typename DynamicPath<Gr>::GraphNode |
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573 | DynamicPath<Gr>::graphNode(const NodeIt& n) const { |
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574 | if( n.idx < length() ) { |
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575 | return n.tail ? G.tail(edges[n.idx]) : G.head(edges[n.idx]); |
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576 | } |
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577 | else if( n.idx == length() ) { |
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578 | return _last; |
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579 | } |
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580 | else { |
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581 | return INVALID; |
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582 | } |
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583 | } |
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584 | |
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585 | template<typename Gr> |
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586 | typename DynamicPath<Gr>::EdgeIt& |
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587 | DynamicPath<Gr>::nth(EdgeIt &e, size_t k) const { |
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588 | if( k>=length() ) { |
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589 | // FIXME: invalid EdgeIt |
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590 | e.it = edges.end(); |
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591 | e.forw = true; |
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592 | return e; |
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593 | } |
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594 | |
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595 | e.it = edges.begin()+k; |
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596 | if(k==0) { |
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597 | e.forw = ( G.tail(*e.it) == _first ); |
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598 | } |
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599 | else { |
---|
600 | e.forw = ( G.tail(*e.it) == G.tail(edges[k-1]) || |
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601 | G.tail(*e.it) == G.head(edges[k-1]) ); |
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602 | } |
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603 | return e; |
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604 | } |
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605 | |
---|
606 | template<typename Gr> |
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607 | typename DynamicPath<Gr>::NodeIt& |
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608 | DynamicPath<Gr>::nth(NodeIt &n, size_t k) const { |
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609 | if( k>length() ) { |
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610 | // FIXME: invalid NodeIt |
---|
611 | n.idx = length()+1; |
---|
612 | n.tail = true; |
---|
613 | return n; |
---|
614 | } |
---|
615 | if( k==length() ) { |
---|
616 | n.idx = length(); |
---|
617 | n.tail = true; |
---|
618 | return n; |
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619 | } |
---|
620 | n = tail(nth<EdgeIt>(k)); |
---|
621 | return n; |
---|
622 | } |
---|
623 | |
---|
624 | // Reszut konstruktorok: |
---|
625 | |
---|
626 | |
---|
627 | template<typename Gr> |
---|
628 | DynamicPath<Gr>::DynamicPath(const DynamicPath &P, const EdgeIt &a, |
---|
629 | const EdgeIt &b) : |
---|
630 | G(P.G), edges(a.it, b.it) // WARNING: if b.it < a.it this will blow up! |
---|
631 | { |
---|
632 | if( G.valid(P._first) && a.it < P.edges.end() ) { |
---|
633 | _first = ( a.forw ? G.tail(*a.it) : G.head(*a.it) ); |
---|
634 | if( b.it < P.edges.end() ) { |
---|
635 | _last = ( b.forw ? G.tail(*b.it) : G.head(*b.it) ); |
---|
636 | } |
---|
637 | else { |
---|
638 | _last = P._last; |
---|
639 | } |
---|
640 | } |
---|
641 | } |
---|
642 | |
---|
643 | template<typename Gr> |
---|
644 | DynamicPath<Gr>::DynamicPath(const DynamicPath &P, const NodeIt &a, |
---|
645 | const NodeIt &b) : G(P.G) |
---|
646 | { |
---|
647 | if( !P.valid(a) || !P.valid(b) ) |
---|
648 | return; |
---|
649 | |
---|
650 | int ai = a.idx, bi = b.idx; |
---|
651 | if( bi<ai ) |
---|
652 | std::swap(ai,bi); |
---|
653 | |
---|
654 | edges.resize(bi-ai); |
---|
655 | copy(P.edges.begin()+ai, P.edges.begin()+bi, edges.begin()); |
---|
656 | |
---|
657 | _first = P.graphNode(a); |
---|
658 | _last = P.graphNode(b); |
---|
659 | } |
---|
660 | |
---|
661 | ///@} |
---|
662 | |
---|
663 | } // namespace hugo |
---|
664 | |
---|
665 | #endif // HUGO_PATH_H |
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