[2260] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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| 5 | * Copyright (C) 2003-2006 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | ///\ingroup concept |
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| 20 | ///\file |
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| 21 | ///\brief Classes for representing paths in graphs. |
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| 22 | /// |
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| 23 | ///\todo Iterators have obsolete style |
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| 24 | |
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| 25 | #ifndef LEMON_CONCEPT_PATH_H |
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| 26 | #define LEMON_CONCEPT_PATH_H |
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| 27 | |
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| 28 | #include <lemon/bits/invalid.h> |
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| 29 | #include <lemon/concept_check.h> |
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| 30 | |
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| 31 | namespace lemon { |
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| 32 | namespace concepts { |
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| 33 | /// \addtogroup concept |
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| 34 | /// @{ |
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| 35 | |
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| 36 | |
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| 37 | //! \brief A skeleton structure for representing directed paths in a graph. |
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| 38 | //! |
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| 39 | //! A skeleton structure for representing directed paths in a graph. |
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| 40 | //! \param _Graph The graph type in which the path is. |
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| 41 | //! |
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| 42 | //! In a sense, the path can be treated as a graph, for it has \c NodeIt |
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| 43 | //! and \c EdgeIt with the same usage. These types converts to the \c Node |
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| 44 | //! and \c Edge of the original graph. |
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| 45 | template<typename _Graph> |
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| 46 | class Path { |
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| 47 | public: |
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| 48 | |
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| 49 | /// Type of the underlying graph. |
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| 50 | typedef _Graph Graph; |
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| 51 | /// Edge type of the underlying graph. |
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| 52 | typedef typename Graph::Edge Edge; |
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| 53 | /// Node type of the underlying graph. |
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| 54 | typedef typename Graph::Node Node; |
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| 55 | |
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| 56 | class NodeIt; |
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| 57 | class EdgeIt; |
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| 58 | |
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| 59 | /// \param _g The graph in which the path is. |
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| 60 | /// |
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| 61 | Path(const Graph &_g) { |
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| 62 | ignore_unused_variable_warning(_g); |
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| 63 | } |
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| 64 | |
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| 65 | /// Length of the path ie. the number of edges in the path. |
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| 66 | int length() const {return 0;} |
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| 67 | |
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| 68 | /// Returns whether the path is empty. |
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| 69 | bool empty() const { return true;} |
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| 70 | |
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| 71 | /// Resets the path to an empty path. |
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| 72 | void clear() {} |
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| 73 | |
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| 74 | /// \brief Starting point of the path. |
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| 75 | /// |
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| 76 | /// Starting point of the path. |
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| 77 | /// Returns INVALID if the path is empty. |
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| 78 | Node target() const {return INVALID;} |
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| 79 | /// \brief End point of the path. |
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| 80 | /// |
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| 81 | /// End point of the path. |
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| 82 | /// Returns INVALID if the path is empty. |
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| 83 | Node source() const {return INVALID;} |
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| 84 | |
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| 85 | /// \brief The target of an edge. |
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| 86 | /// |
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| 87 | /// Returns node iterator pointing to the target node of the |
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| 88 | /// given edge iterator. |
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| 89 | NodeIt target(const EdgeIt&) const {return INVALID;} |
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| 90 | |
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| 91 | /// \brief The source of an edge. |
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| 92 | /// |
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| 93 | /// Returns node iterator pointing to the source node of the |
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| 94 | /// given edge iterator. |
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| 95 | NodeIt source(const EdgeIt&) const {return INVALID;} |
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| 96 | |
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| 97 | /// \brief Iterator class to iterate on the nodes of the paths |
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| 98 | /// |
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| 99 | /// This class is used to iterate on the nodes of the paths |
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| 100 | /// |
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| 101 | /// Of course it converts to Graph::Node. |
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| 102 | class NodeIt { |
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| 103 | public: |
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| 104 | /// Default constructor |
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| 105 | NodeIt() {} |
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| 106 | /// Invalid constructor |
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| 107 | NodeIt(Invalid) {} |
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| 108 | /// Constructor with starting point |
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| 109 | NodeIt(const Path &) {} |
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| 110 | |
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| 111 | ///Conversion to Graph::Node |
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| 112 | operator Node() const { return INVALID; } |
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| 113 | /// Next node |
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| 114 | NodeIt& operator++() {return *this;} |
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| 115 | |
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| 116 | /// Comparison operator |
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| 117 | bool operator==(const NodeIt&) const {return true;} |
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| 118 | /// Comparison operator |
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| 119 | bool operator!=(const NodeIt&) const {return true;} |
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| 120 | /// Comparison operator |
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| 121 | bool operator<(const NodeIt&) const {return false;} |
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| 122 | |
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| 123 | }; |
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| 124 | |
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| 125 | /// \brief Iterator class to iterate on the edges of the paths |
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| 126 | /// |
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| 127 | /// This class is used to iterate on the edges of the paths |
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| 128 | /// |
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| 129 | /// Of course it converts to Graph::Edge |
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| 130 | class EdgeIt { |
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| 131 | public: |
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| 132 | /// Default constructor |
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| 133 | EdgeIt() {} |
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| 134 | /// Invalid constructor |
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| 135 | EdgeIt(Invalid) {} |
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| 136 | /// Constructor with starting point |
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| 137 | EdgeIt(const Path &) {} |
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| 138 | |
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| 139 | operator Edge() const { return INVALID; } |
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| 140 | |
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| 141 | /// Next edge |
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| 142 | EdgeIt& operator++() {return *this;} |
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| 143 | |
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| 144 | /// Comparison operator |
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| 145 | bool operator==(const EdgeIt&) const {return true;} |
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| 146 | /// Comparison operator |
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| 147 | bool operator!=(const EdgeIt&) const {return true;} |
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| 148 | /// Comparison operator |
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| 149 | bool operator<(const EdgeIt&) const {return false;} |
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| 150 | |
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| 151 | }; |
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| 152 | |
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| 153 | |
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| 154 | friend class Builder; |
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| 155 | |
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| 156 | /// \brief Class to build paths |
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| 157 | /// |
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| 158 | /// This class is used to fill a path with edges. |
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| 159 | /// |
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| 160 | /// You can push new edges to the front and to the back of the path in |
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| 161 | /// arbitrary order then you should commit these changes to the graph. |
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| 162 | /// |
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| 163 | /// While the builder is active (after the first modifying |
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| 164 | /// operation and until the call of \ref commit()) the |
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| 165 | /// underlining Path is in a "transitional" state (operations on |
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| 166 | /// it have undefined result). |
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| 167 | class Builder { |
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| 168 | public: |
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| 169 | |
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| 170 | /// Constructor |
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| 171 | |
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| 172 | /// Constructor |
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| 173 | /// \param _path the path you want to fill in. |
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| 174 | /// |
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| 175 | |
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| 176 | Builder(Path &_path) { ignore_unused_variable_warning(_path); } |
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| 177 | |
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| 178 | /// Sets the starting node of the path. |
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| 179 | |
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| 180 | /// Sets the starting node of the path. Edge added to the path |
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| 181 | /// afterwards have to be incident to this node. |
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| 182 | /// You \em must start building an empty path with these functions. |
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| 183 | /// (And you \em must \em not use it later). |
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| 184 | /// \sa pushFront() |
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| 185 | /// \sa pushBack() |
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| 186 | void setStartNode(const Node &) {} |
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| 187 | |
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| 188 | ///Push a new edge to the front of the path |
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| 189 | |
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| 190 | ///Push a new edge to the front of the path. |
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| 191 | ///If the path is empty, you \em must call \ref setStartNode() before |
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| 192 | ///the first use of \ref pushFront(). |
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| 193 | void pushFront(const Edge&) {} |
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| 194 | |
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| 195 | ///Push a new edge to the back of the path |
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| 196 | |
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| 197 | ///Push a new edge to the back of the path. |
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| 198 | ///If the path is empty, you \em must call \ref setStartNode() before |
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| 199 | ///the first use of \ref pushBack(). |
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| 200 | void pushBack(const Edge&) {} |
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| 201 | |
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| 202 | ///Commit the changes to the path. |
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| 203 | |
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| 204 | ///Commit the changes to the path. |
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| 205 | /// |
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| 206 | void commit() {} |
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| 207 | |
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| 208 | ///Reserve (front) storage for the builder in advance. |
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| 209 | |
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| 210 | ///If you know a reasonable upper bound on the number of the edges |
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| 211 | ///to add to the front of the path, |
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| 212 | ///using this function you may speed up the building. |
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| 213 | void reserveFront(size_t) {} |
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| 214 | ///Reserve (back) storage for the builder in advance. |
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| 215 | |
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| 216 | ///If you know a reasonable upper bound on the number of the edges |
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| 217 | ///to add to the back of the path, |
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| 218 | ///using this function you may speed up the building. |
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| 219 | void reserveBack(size_t) {} |
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| 220 | }; |
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| 221 | |
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| 222 | template <typename _Path> |
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| 223 | struct Constraints { |
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| 224 | void constraints() { |
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| 225 | typedef typename _Path::Node Node; |
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| 226 | typedef typename _Path::NodeIt NodeIt; |
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| 227 | typedef typename Graph::Node GraphNode; |
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| 228 | |
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| 229 | typedef typename _Path::Edge Edge; |
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| 230 | typedef typename _Path::EdgeIt EdgeIt; |
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| 231 | typedef typename Graph::Edge GraphEdge; |
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| 232 | |
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| 233 | typedef typename _Path::Builder Builder; |
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| 234 | |
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| 235 | path = _Path(graph); |
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| 236 | |
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| 237 | bool b = cpath.empty(); |
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| 238 | int l = cpath.length(); |
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| 239 | |
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| 240 | Node gn; |
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| 241 | Edge ge; |
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| 242 | gn = cpath.source(); |
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| 243 | gn = cpath.target(); |
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| 244 | |
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| 245 | NodeIt nit; |
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| 246 | EdgeIt eit(INVALID); |
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| 247 | nit = path.source(eit); |
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| 248 | nit = path.target(eit); |
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| 249 | |
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| 250 | nit = NodeIt(); |
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| 251 | nit = NodeIt(cpath); |
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| 252 | nit = INVALID; |
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| 253 | gn = nit; |
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| 254 | ++nit; |
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| 255 | b = nit == nit; |
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| 256 | b = nit != nit; |
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| 257 | b = nit < nit; |
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| 258 | |
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| 259 | eit = EdgeIt(); |
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| 260 | eit = EdgeIt(cpath); |
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| 261 | eit = INVALID; |
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| 262 | ge = eit; |
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| 263 | ++eit; |
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| 264 | b = eit == eit; |
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| 265 | b = eit != eit; |
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| 266 | b = eit < eit; |
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| 267 | |
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| 268 | size_t st = 0; |
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| 269 | |
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| 270 | Builder builder(path); |
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| 271 | builder.setStartNode(gn); |
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| 272 | builder.pushFront(ge); |
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| 273 | builder.pushBack(ge); |
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| 274 | builder.commit(); |
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| 275 | builder.reserveFront(st); |
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| 276 | builder.reserveBack(st); |
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| 277 | |
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| 278 | ignore_unused_variable_warning(l); |
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| 279 | ignore_unused_variable_warning(b); |
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| 280 | } |
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| 281 | |
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| 282 | const Graph& graph; |
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| 283 | const _Path& cpath; |
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| 284 | _Path& path; |
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| 285 | }; |
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| 286 | |
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| 287 | }; |
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| 288 | |
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| 289 | ///@} |
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| 290 | } |
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| 291 | |
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| 292 | } // namespace lemon |
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| 293 | |
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| 294 | #endif // LEMON_CONCEPT_PATH_H |
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