[209] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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[96] | 2 | * |
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[209] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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[96] | 4 | * |
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[1270] | 5 | * Copyright (C) 2003-2013 |
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[96] | 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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[832] | 21 | ///\brief The concept of paths |
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[96] | 22 | /// |
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| 23 | |
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[576] | 24 | #ifndef LEMON_CONCEPTS_PATH_H |
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| 25 | #define LEMON_CONCEPTS_PATH_H |
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[96] | 26 | |
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[220] | 27 | #include <lemon/core.h> |
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[96] | 28 | #include <lemon/concept_check.h> |
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[1336] | 29 | #include <lemon/bits/stl_iterators.h> |
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[96] | 30 | |
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| 31 | namespace lemon { |
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| 32 | namespace concepts { |
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| 33 | |
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| 34 | /// \addtogroup concept |
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| 35 | /// @{ |
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| 36 | |
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| 37 | /// \brief A skeleton structure for representing directed paths in |
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| 38 | /// a digraph. |
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| 39 | /// |
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| 40 | /// A skeleton structure for representing directed paths in a |
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[209] | 41 | /// digraph. |
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[832] | 42 | /// In a sense, a path can be treated as a list of arcs. |
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| 43 | /// LEMON path types just store this list. As a consequence, they cannot |
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| 44 | /// enumerate the nodes on the path directly and a zero length path |
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| 45 | /// cannot store its source node. |
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| 46 | /// |
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| 47 | /// The arcs of a path should be stored in the order of their directions, |
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| 48 | /// i.e. the target node of each arc should be the same as the source |
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| 49 | /// node of the next arc. This consistency could be checked using |
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| 50 | /// \ref checkPath(). |
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| 51 | /// The source and target nodes of a (consistent) path can be obtained |
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| 52 | /// using \ref pathSource() and \ref pathTarget(). |
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| 53 | /// |
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| 54 | /// A path can be constructed from another path of any type using the |
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| 55 | /// copy constructor or the assignment operator. |
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| 56 | /// |
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[606] | 57 | /// \tparam GR The digraph type in which the path is. |
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| 58 | template <typename GR> |
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[96] | 59 | class Path { |
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| 60 | public: |
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| 61 | |
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| 62 | /// Type of the underlying digraph. |
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[606] | 63 | typedef GR Digraph; |
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[96] | 64 | /// Arc type of the underlying digraph. |
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| 65 | typedef typename Digraph::Arc Arc; |
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| 66 | |
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| 67 | class ArcIt; |
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| 68 | |
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| 69 | /// \brief Default constructor |
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| 70 | Path() {} |
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| 71 | |
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[832] | 72 | /// \brief Template copy constructor |
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[96] | 73 | template <typename CPath> |
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[1416] | 74 | Path(const CPath& cpath) { |
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| 75 | ::lemon::ignore_unused_variable_warning(cpath); |
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| 76 | } |
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[96] | 77 | |
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[832] | 78 | /// \brief Template assigment operator |
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[96] | 79 | template <typename CPath> |
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[278] | 80 | Path& operator=(const CPath& cpath) { |
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[1257] | 81 | ::lemon::ignore_unused_variable_warning(cpath); |
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[278] | 82 | return *this; |
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| 83 | } |
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[96] | 84 | |
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[832] | 85 | /// Length of the path, i.e. the number of arcs on the path. |
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[96] | 86 | int length() const { return 0;} |
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| 87 | |
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| 88 | /// Returns whether the path is empty. |
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| 89 | bool empty() const { return true;} |
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| 90 | |
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| 91 | /// Resets the path to an empty path. |
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| 92 | void clear() {} |
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| 93 | |
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[832] | 94 | /// \brief LEMON style iterator for enumerating the arcs of a path. |
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[96] | 95 | /// |
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[832] | 96 | /// LEMON style iterator class for enumerating the arcs of a path. |
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[96] | 97 | class ArcIt { |
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| 98 | public: |
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[209] | 99 | /// Default constructor |
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| 100 | ArcIt() {} |
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| 101 | /// Invalid constructor |
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| 102 | ArcIt(Invalid) {} |
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[832] | 103 | /// Sets the iterator to the first arc of the given path |
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[209] | 104 | ArcIt(const Path &) {} |
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[96] | 105 | |
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[832] | 106 | /// Conversion to \c Arc |
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[209] | 107 | operator Arc() const { return INVALID; } |
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[96] | 108 | |
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[209] | 109 | /// Next arc |
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| 110 | ArcIt& operator++() {return *this;} |
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[96] | 111 | |
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[209] | 112 | /// Comparison operator |
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| 113 | bool operator==(const ArcIt&) const {return true;} |
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| 114 | /// Comparison operator |
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| 115 | bool operator!=(const ArcIt&) const {return true;} |
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[212] | 116 | /// Comparison operator |
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| 117 | bool operator<(const ArcIt&) const {return false;} |
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[96] | 118 | |
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| 119 | }; |
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| 120 | |
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[1336] | 121 | /// \brief Gets the collection of the arcs of the path. |
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| 122 | /// |
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| 123 | /// This function can be used for iterating on the |
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| 124 | /// arcs of the path. It returns a wrapped |
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| 125 | /// ArcIt, which looks like an STL container |
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| 126 | /// (by having begin() and end()) which you can use in range-based |
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| 127 | /// for loops, STL algorithms, etc. |
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| 128 | /// For example you can write: |
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| 129 | ///\code |
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| 130 | /// for(auto a: p.arcs()) |
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| 131 | /// doSomething(a); |
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| 132 | ///\endcode |
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| 133 | LemonRangeWrapper1<ArcIt, Path> arcs() const { |
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| 134 | return LemonRangeWrapper1<ArcIt, Path>(*this); |
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| 135 | } |
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| 136 | |
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| 137 | |
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[96] | 138 | template <typename _Path> |
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| 139 | struct Constraints { |
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| 140 | void constraints() { |
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| 141 | Path<Digraph> pc; |
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| 142 | _Path p, pp(pc); |
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| 143 | int l = p.length(); |
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| 144 | int e = p.empty(); |
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| 145 | p.clear(); |
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| 146 | |
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| 147 | p = pc; |
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| 148 | |
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| 149 | typename _Path::ArcIt id, ii(INVALID), i(p); |
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| 150 | |
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| 151 | ++i; |
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| 152 | typename Digraph::Arc ed = i; |
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| 153 | |
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| 154 | e = (i == ii); |
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| 155 | e = (i != ii); |
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| 156 | e = (i < ii); |
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| 157 | |
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[1257] | 158 | ::lemon::ignore_unused_variable_warning(l); |
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| 159 | ::lemon::ignore_unused_variable_warning(pp); |
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| 160 | ::lemon::ignore_unused_variable_warning(e); |
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| 161 | ::lemon::ignore_unused_variable_warning(id); |
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| 162 | ::lemon::ignore_unused_variable_warning(ii); |
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| 163 | ::lemon::ignore_unused_variable_warning(ed); |
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[96] | 164 | } |
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| 165 | }; |
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| 166 | |
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| 167 | }; |
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| 168 | |
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| 169 | namespace _path_bits { |
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[209] | 170 | |
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[96] | 171 | template <typename _Digraph, typename _Path, typename RevPathTag = void> |
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| 172 | struct PathDumperConstraints { |
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| 173 | void constraints() { |
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| 174 | int l = p.length(); |
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| 175 | int e = p.empty(); |
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| 176 | |
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| 177 | typename _Path::ArcIt id, i(p); |
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| 178 | |
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| 179 | ++i; |
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| 180 | typename _Digraph::Arc ed = i; |
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| 181 | |
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| 182 | e = (i == INVALID); |
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| 183 | e = (i != INVALID); |
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| 184 | |
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[1257] | 185 | ::lemon::ignore_unused_variable_warning(l); |
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| 186 | ::lemon::ignore_unused_variable_warning(e); |
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| 187 | ::lemon::ignore_unused_variable_warning(id); |
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| 188 | ::lemon::ignore_unused_variable_warning(ed); |
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[96] | 189 | } |
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| 190 | _Path& p; |
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[1125] | 191 | PathDumperConstraints() {} |
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[96] | 192 | }; |
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| 193 | |
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| 194 | template <typename _Digraph, typename _Path> |
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| 195 | struct PathDumperConstraints< |
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[209] | 196 | _Digraph, _Path, |
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[96] | 197 | typename enable_if<typename _Path::RevPathTag, void>::type |
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| 198 | > { |
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| 199 | void constraints() { |
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| 200 | int l = p.length(); |
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| 201 | int e = p.empty(); |
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| 202 | |
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| 203 | typename _Path::RevArcIt id, i(p); |
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| 204 | |
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| 205 | ++i; |
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| 206 | typename _Digraph::Arc ed = i; |
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| 207 | |
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| 208 | e = (i == INVALID); |
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| 209 | e = (i != INVALID); |
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| 210 | |
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[1257] | 211 | ::lemon::ignore_unused_variable_warning(l); |
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| 212 | ::lemon::ignore_unused_variable_warning(e); |
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| 213 | ::lemon::ignore_unused_variable_warning(id); |
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| 214 | ::lemon::ignore_unused_variable_warning(ed); |
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[96] | 215 | } |
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| 216 | _Path& p; |
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[1125] | 217 | PathDumperConstraints() {} |
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[96] | 218 | }; |
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[209] | 219 | |
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[96] | 220 | } |
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| 221 | |
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| 222 | |
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| 223 | /// \brief A skeleton structure for path dumpers. |
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| 224 | /// |
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| 225 | /// A skeleton structure for path dumpers. The path dumpers are |
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[832] | 226 | /// the generalization of the paths, they can enumerate the arcs |
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| 227 | /// of the path either in forward or in backward order. |
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| 228 | /// These classes are typically not used directly, they are rather |
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| 229 | /// used to be assigned to a real path type. |
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[96] | 230 | /// |
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| 231 | /// The main purpose of this concept is that the shortest path |
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[832] | 232 | /// algorithms can enumerate the arcs easily in reverse order. |
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| 233 | /// In LEMON, such algorithms give back a (reverse) path dumper that |
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| 234 | /// can be assigned to a real path. The dumpers can be implemented as |
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[96] | 235 | /// an adaptor class to the predecessor map. |
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[606] | 236 | /// |
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| 237 | /// \tparam GR The digraph type in which the path is. |
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| 238 | template <typename GR> |
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[96] | 239 | class PathDumper { |
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| 240 | public: |
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| 241 | |
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| 242 | /// Type of the underlying digraph. |
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[606] | 243 | typedef GR Digraph; |
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[96] | 244 | /// Arc type of the underlying digraph. |
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| 245 | typedef typename Digraph::Arc Arc; |
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| 246 | |
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[832] | 247 | /// Length of the path, i.e. the number of arcs on the path. |
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[96] | 248 | int length() const { return 0;} |
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| 249 | |
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| 250 | /// Returns whether the path is empty. |
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| 251 | bool empty() const { return true;} |
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| 252 | |
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| 253 | /// \brief Forward or reverse dumping |
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| 254 | /// |
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[832] | 255 | /// If this tag is defined to be \c True, then reverse dumping |
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| 256 | /// is provided in the path dumper. In this case, \c RevArcIt |
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| 257 | /// iterator should be implemented instead of \c ArcIt iterator. |
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[96] | 258 | typedef False RevPathTag; |
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| 259 | |
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[832] | 260 | /// \brief LEMON style iterator for enumerating the arcs of a path. |
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[96] | 261 | /// |
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[832] | 262 | /// LEMON style iterator class for enumerating the arcs of a path. |
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[96] | 263 | class ArcIt { |
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| 264 | public: |
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[209] | 265 | /// Default constructor |
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| 266 | ArcIt() {} |
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| 267 | /// Invalid constructor |
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| 268 | ArcIt(Invalid) {} |
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[832] | 269 | /// Sets the iterator to the first arc of the given path |
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[209] | 270 | ArcIt(const PathDumper&) {} |
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[96] | 271 | |
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[832] | 272 | /// Conversion to \c Arc |
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[209] | 273 | operator Arc() const { return INVALID; } |
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[96] | 274 | |
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[209] | 275 | /// Next arc |
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| 276 | ArcIt& operator++() {return *this;} |
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[96] | 277 | |
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[209] | 278 | /// Comparison operator |
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| 279 | bool operator==(const ArcIt&) const {return true;} |
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| 280 | /// Comparison operator |
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| 281 | bool operator!=(const ArcIt&) const {return true;} |
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[212] | 282 | /// Comparison operator |
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| 283 | bool operator<(const ArcIt&) const {return false;} |
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[96] | 284 | |
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| 285 | }; |
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| 286 | |
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[1336] | 287 | /// \brief Gets the collection of the arcs of the path. |
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| 288 | /// |
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| 289 | /// This function can be used for iterating on the |
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| 290 | /// arcs of the path. It returns a wrapped |
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| 291 | /// ArcIt, which looks like an STL container |
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| 292 | /// (by having begin() and end()) which you can use in range-based |
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| 293 | /// for loops, STL algorithms, etc. |
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| 294 | /// For example you can write: |
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| 295 | ///\code |
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| 296 | /// for(auto a: p.arcs()) |
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| 297 | /// doSomething(a); |
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| 298 | ///\endcode |
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| 299 | LemonRangeWrapper1<ArcIt, PathDumper> arcs() const { |
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| 300 | return LemonRangeWrapper1<ArcIt, PathDumper>(*this); |
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| 301 | } |
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| 302 | |
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| 303 | |
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[832] | 304 | /// \brief LEMON style iterator for enumerating the arcs of a path |
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| 305 | /// in reverse direction. |
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[96] | 306 | /// |
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[832] | 307 | /// LEMON style iterator class for enumerating the arcs of a path |
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| 308 | /// in reverse direction. |
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[96] | 309 | class RevArcIt { |
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| 310 | public: |
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[209] | 311 | /// Default constructor |
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| 312 | RevArcIt() {} |
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| 313 | /// Invalid constructor |
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| 314 | RevArcIt(Invalid) {} |
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[832] | 315 | /// Sets the iterator to the last arc of the given path |
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[209] | 316 | RevArcIt(const PathDumper &) {} |
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[96] | 317 | |
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[832] | 318 | /// Conversion to \c Arc |
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[209] | 319 | operator Arc() const { return INVALID; } |
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[96] | 320 | |
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[209] | 321 | /// Next arc |
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| 322 | RevArcIt& operator++() {return *this;} |
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[96] | 323 | |
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[209] | 324 | /// Comparison operator |
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| 325 | bool operator==(const RevArcIt&) const {return true;} |
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| 326 | /// Comparison operator |
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| 327 | bool operator!=(const RevArcIt&) const {return true;} |
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[212] | 328 | /// Comparison operator |
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| 329 | bool operator<(const RevArcIt&) const {return false;} |
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[96] | 330 | |
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| 331 | }; |
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| 332 | |
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[1336] | 333 | /// \brief Gets the collection of the arcs of the path |
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| 334 | /// in reverse direction. |
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| 335 | /// |
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| 336 | /// This function can be used for iterating on the |
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| 337 | /// arcs of the path in reverse direction. It returns a wrapped |
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| 338 | /// RevArcIt, which looks like an STL container |
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| 339 | /// (by having begin() and end()) which you can use in range-based |
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| 340 | /// for loops, STL algorithms, etc. |
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| 341 | /// For example you can write: |
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| 342 | ///\code |
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| 343 | /// for(auto a: p.revArcs()) |
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| 344 | /// doSomething(a); |
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| 345 | ///\endcode |
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| 346 | LemonRangeWrapper1<RevArcIt, PathDumper> revArcs() const { |
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| 347 | return LemonRangeWrapper1<RevArcIt, PathDumper>(*this); |
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| 348 | } |
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| 349 | |
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| 350 | |
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[96] | 351 | template <typename _Path> |
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| 352 | struct Constraints { |
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| 353 | void constraints() { |
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| 354 | function_requires<_path_bits:: |
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| 355 | PathDumperConstraints<Digraph, _Path> >(); |
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| 356 | } |
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| 357 | }; |
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| 358 | |
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| 359 | }; |
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| 360 | |
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| 361 | |
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| 362 | ///@} |
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| 363 | } |
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| 364 | |
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| 365 | } // namespace lemon |
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| 366 | |
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[576] | 367 | #endif |
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