[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 paths |
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| 20 | ///\file |
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| 21 | ///\brief Classes for representing paths in digraphs. |
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| 22 | /// |
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| 23 | |
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| 24 | #ifndef LEMON_PATH_H |
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| 25 | #define LEMON_PATH_H |
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| 26 | |
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| 27 | #include <vector> |
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| 28 | #include <algorithm> |
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| 29 | |
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| 30 | #include <lemon/error.h> |
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[220] | 31 | #include <lemon/core.h> |
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[100] | 32 | #include <lemon/concepts/path.h> |
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[1336] | 33 | #include <lemon/bits/stl_iterators.h> |
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[96] | 34 | |
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| 35 | namespace lemon { |
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| 36 | |
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| 37 | /// \addtogroup paths |
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| 38 | /// @{ |
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| 39 | |
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| 40 | |
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| 41 | /// \brief A structure for representing directed paths in a digraph. |
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| 42 | /// |
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| 43 | /// A structure for representing directed path in a digraph. |
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[606] | 44 | /// \tparam GR The digraph type in which the path is. |
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[96] | 45 | /// |
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| 46 | /// In a sense, the path can be treated as a list of arcs. The |
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[1024] | 47 | /// LEMON path type stores just this list. As a consequence, it |
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[97] | 48 | /// cannot enumerate the nodes of the path and the source node of |
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| 49 | /// a zero length path is undefined. |
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[96] | 50 | /// |
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| 51 | /// This implementation is a back and front insertable and erasable |
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| 52 | /// path type. It can be indexed in O(1) time. The front and back |
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[97] | 53 | /// insertion and erase is done in O(1) (amortized) time. The |
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| 54 | /// implementation uses two vectors for storing the front and back |
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| 55 | /// insertions. |
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[606] | 56 | template <typename GR> |
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[96] | 57 | class Path { |
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| 58 | public: |
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| 59 | |
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[606] | 60 | typedef GR Digraph; |
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[96] | 61 | typedef typename Digraph::Arc Arc; |
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| 62 | |
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| 63 | /// \brief Default constructor |
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| 64 | /// |
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| 65 | /// Default constructor |
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| 66 | Path() {} |
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| 67 | |
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[1144] | 68 | /// \brief Copy constructor |
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| 69 | /// |
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| 70 | Path(const Path& cpath) { |
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| 71 | pathCopy(cpath, *this); |
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| 72 | } |
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| 73 | |
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[96] | 74 | /// \brief Template copy constructor |
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| 75 | /// |
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[97] | 76 | /// This constuctor initializes the path from any other path type. |
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| 77 | /// It simply makes a copy of the given path. |
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[96] | 78 | template <typename CPath> |
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| 79 | Path(const CPath& cpath) { |
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[551] | 80 | pathCopy(cpath, *this); |
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[96] | 81 | } |
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| 82 | |
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[1144] | 83 | /// \brief Copy assignment |
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| 84 | /// |
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| 85 | Path& operator=(const Path& cpath) { |
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| 86 | pathCopy(cpath, *this); |
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| 87 | return *this; |
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| 88 | } |
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| 89 | |
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[96] | 90 | /// \brief Template copy assignment |
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| 91 | /// |
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[97] | 92 | /// This operator makes a copy of a path of any other type. |
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[96] | 93 | template <typename CPath> |
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| 94 | Path& operator=(const CPath& cpath) { |
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[551] | 95 | pathCopy(cpath, *this); |
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[96] | 96 | return *this; |
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| 97 | } |
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| 98 | |
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[236] | 99 | /// \brief LEMON style iterator for path arcs |
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[96] | 100 | /// |
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| 101 | /// This class is used to iterate on the arcs of the paths. |
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| 102 | class ArcIt { |
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| 103 | friend class Path; |
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| 104 | public: |
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| 105 | /// \brief Default constructor |
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| 106 | ArcIt() {} |
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| 107 | /// \brief Invalid constructor |
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| 108 | ArcIt(Invalid) : path(0), idx(-1) {} |
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[97] | 109 | /// \brief Initializate the iterator to the first arc of path |
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[209] | 110 | ArcIt(const Path &_path) |
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[96] | 111 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
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| 112 | |
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| 113 | private: |
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| 114 | |
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[209] | 115 | ArcIt(const Path &_path, int _idx) |
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[96] | 116 | : path(&_path), idx(_idx) {} |
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| 117 | |
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| 118 | public: |
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| 119 | |
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| 120 | /// \brief Conversion to Arc |
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| 121 | operator const Arc&() const { |
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| 122 | return path->nth(idx); |
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| 123 | } |
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| 124 | |
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| 125 | /// \brief Next arc |
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[209] | 126 | ArcIt& operator++() { |
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[96] | 127 | ++idx; |
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[209] | 128 | if (idx >= path->length()) idx = -1; |
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| 129 | return *this; |
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[96] | 130 | } |
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| 131 | |
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| 132 | /// \brief Comparison operator |
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| 133 | bool operator==(const ArcIt& e) const { return idx==e.idx; } |
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| 134 | /// \brief Comparison operator |
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| 135 | bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
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| 136 | /// \brief Comparison operator |
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| 137 | bool operator<(const ArcIt& e) const { return idx<e.idx; } |
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| 138 | |
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| 139 | private: |
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| 140 | const Path *path; |
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| 141 | int idx; |
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| 142 | }; |
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| 143 | |
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[1336] | 144 | /// \brief Gets the collection of the arcs of the path. |
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| 145 | /// |
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| 146 | /// This function can be used for iterating on the |
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| 147 | /// arcs of the path. It returns a wrapped |
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| 148 | /// ArcIt, which looks like an STL container |
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| 149 | /// (by having begin() and end()) which you can use in range-based |
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| 150 | /// for loops, STL algorithms, etc. |
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| 151 | /// For example you can write: |
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| 152 | ///\code |
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| 153 | /// for(auto a: p.arcs()) |
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| 154 | /// doSomething(a); |
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| 155 | ///\endcode |
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| 156 | LemonRangeWrapper1<ArcIt, Path> arcs() const { |
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| 157 | return LemonRangeWrapper1<ArcIt, Path>(*this); |
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| 158 | } |
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| 159 | |
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| 160 | |
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[96] | 161 | /// \brief Length of the path. |
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| 162 | int length() const { return head.size() + tail.size(); } |
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[97] | 163 | /// \brief Return whether the path is empty. |
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[96] | 164 | bool empty() const { return head.empty() && tail.empty(); } |
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| 165 | |
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[97] | 166 | /// \brief Reset the path to an empty one. |
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[96] | 167 | void clear() { head.clear(); tail.clear(); } |
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| 168 | |
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[1024] | 169 | /// \brief The n-th arc. |
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[96] | 170 | /// |
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[606] | 171 | /// \pre \c n is in the <tt>[0..length() - 1]</tt> range. |
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[96] | 172 | const Arc& nth(int n) const { |
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| 173 | return n < int(head.size()) ? *(head.rbegin() + n) : |
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| 174 | *(tail.begin() + (n - head.size())); |
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| 175 | } |
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| 176 | |
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[1024] | 177 | /// \brief Initialize arc iterator to point to the n-th arc |
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[96] | 178 | /// |
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[606] | 179 | /// \pre \c n is in the <tt>[0..length() - 1]</tt> range. |
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[96] | 180 | ArcIt nthIt(int n) const { |
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| 181 | return ArcIt(*this, n); |
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| 182 | } |
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| 183 | |
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[97] | 184 | /// \brief The first arc of the path |
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[96] | 185 | const Arc& front() const { |
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| 186 | return head.empty() ? tail.front() : head.back(); |
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| 187 | } |
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| 188 | |
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| 189 | /// \brief Add a new arc before the current path |
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| 190 | void addFront(const Arc& arc) { |
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| 191 | head.push_back(arc); |
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| 192 | } |
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| 193 | |
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| 194 | /// \brief Erase the first arc of the path |
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| 195 | void eraseFront() { |
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| 196 | if (!head.empty()) { |
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| 197 | head.pop_back(); |
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| 198 | } else { |
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| 199 | head.clear(); |
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| 200 | int halfsize = tail.size() / 2; |
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| 201 | head.resize(halfsize); |
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| 202 | std::copy(tail.begin() + 1, tail.begin() + halfsize + 1, |
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| 203 | head.rbegin()); |
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| 204 | std::copy(tail.begin() + halfsize + 1, tail.end(), tail.begin()); |
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| 205 | tail.resize(tail.size() - halfsize - 1); |
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| 206 | } |
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| 207 | } |
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| 208 | |
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[97] | 209 | /// \brief The last arc of the path |
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[96] | 210 | const Arc& back() const { |
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| 211 | return tail.empty() ? head.front() : tail.back(); |
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| 212 | } |
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| 213 | |
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| 214 | /// \brief Add a new arc behind the current path |
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| 215 | void addBack(const Arc& arc) { |
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| 216 | tail.push_back(arc); |
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| 217 | } |
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| 218 | |
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| 219 | /// \brief Erase the last arc of the path |
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| 220 | void eraseBack() { |
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| 221 | if (!tail.empty()) { |
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| 222 | tail.pop_back(); |
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| 223 | } else { |
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| 224 | int halfsize = head.size() / 2; |
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| 225 | tail.resize(halfsize); |
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| 226 | std::copy(head.begin() + 1, head.begin() + halfsize + 1, |
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| 227 | tail.rbegin()); |
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| 228 | std::copy(head.begin() + halfsize + 1, head.end(), head.begin()); |
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| 229 | head.resize(head.size() - halfsize - 1); |
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| 230 | } |
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| 231 | } |
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| 232 | |
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| 233 | typedef True BuildTag; |
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| 234 | |
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| 235 | template <typename CPath> |
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| 236 | void build(const CPath& path) { |
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| 237 | int len = path.length(); |
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| 238 | tail.reserve(len); |
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| 239 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
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| 240 | tail.push_back(it); |
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| 241 | } |
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| 242 | } |
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| 243 | |
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| 244 | template <typename CPath> |
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| 245 | void buildRev(const CPath& path) { |
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| 246 | int len = path.length(); |
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| 247 | head.reserve(len); |
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| 248 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
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| 249 | head.push_back(it); |
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| 250 | } |
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| 251 | } |
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| 252 | |
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| 253 | protected: |
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| 254 | typedef std::vector<Arc> Container; |
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| 255 | Container head, tail; |
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| 256 | |
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| 257 | }; |
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| 258 | |
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| 259 | /// \brief A structure for representing directed paths in a digraph. |
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| 260 | /// |
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| 261 | /// A structure for representing directed path in a digraph. |
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[606] | 262 | /// \tparam GR The digraph type in which the path is. |
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[96] | 263 | /// |
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| 264 | /// In a sense, the path can be treated as a list of arcs. The |
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[1024] | 265 | /// LEMON path type stores just this list. As a consequence it |
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[96] | 266 | /// cannot enumerate the nodes in the path and the zero length paths |
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| 267 | /// cannot store the source. |
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| 268 | /// |
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| 269 | /// This implementation is a just back insertable and erasable path |
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| 270 | /// type. It can be indexed in O(1) time. The back insertion and |
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| 271 | /// erasure is amortized O(1) time. This implementation is faster |
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| 272 | /// then the \c Path type because it use just one vector for the |
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| 273 | /// arcs. |
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[606] | 274 | template <typename GR> |
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[96] | 275 | class SimplePath { |
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| 276 | public: |
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| 277 | |
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[606] | 278 | typedef GR Digraph; |
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[96] | 279 | typedef typename Digraph::Arc Arc; |
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| 280 | |
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| 281 | /// \brief Default constructor |
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| 282 | /// |
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| 283 | /// Default constructor |
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| 284 | SimplePath() {} |
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| 285 | |
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[1144] | 286 | /// \brief Copy constructor |
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| 287 | /// |
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| 288 | SimplePath(const SimplePath& cpath) { |
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| 289 | pathCopy(cpath, *this); |
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| 290 | } |
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| 291 | |
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[96] | 292 | /// \brief Template copy constructor |
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| 293 | /// |
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| 294 | /// This path can be initialized with any other path type. It just |
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| 295 | /// makes a copy of the given path. |
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| 296 | template <typename CPath> |
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| 297 | SimplePath(const CPath& cpath) { |
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[551] | 298 | pathCopy(cpath, *this); |
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[96] | 299 | } |
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| 300 | |
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[1144] | 301 | /// \brief Copy assignment |
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| 302 | /// |
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| 303 | SimplePath& operator=(const SimplePath& cpath) { |
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| 304 | pathCopy(cpath, *this); |
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| 305 | return *this; |
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| 306 | } |
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| 307 | |
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[96] | 308 | /// \brief Template copy assignment |
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| 309 | /// |
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| 310 | /// This path can be initialized with any other path type. It just |
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| 311 | /// makes a copy of the given path. |
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| 312 | template <typename CPath> |
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| 313 | SimplePath& operator=(const CPath& cpath) { |
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[551] | 314 | pathCopy(cpath, *this); |
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[96] | 315 | return *this; |
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| 316 | } |
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| 317 | |
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| 318 | /// \brief Iterator class to iterate on the arcs of the paths |
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| 319 | /// |
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| 320 | /// This class is used to iterate on the arcs of the paths |
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| 321 | /// |
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| 322 | /// Of course it converts to Digraph::Arc |
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| 323 | class ArcIt { |
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| 324 | friend class SimplePath; |
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| 325 | public: |
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| 326 | /// Default constructor |
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| 327 | ArcIt() {} |
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| 328 | /// Invalid constructor |
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| 329 | ArcIt(Invalid) : path(0), idx(-1) {} |
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| 330 | /// \brief Initializate the constructor to the first arc of path |
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[209] | 331 | ArcIt(const SimplePath &_path) |
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[96] | 332 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
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| 333 | |
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| 334 | private: |
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| 335 | |
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| 336 | /// Constructor with starting point |
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[209] | 337 | ArcIt(const SimplePath &_path, int _idx) |
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[1212] | 338 | : path(&_path), idx(_idx) {} |
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[96] | 339 | |
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| 340 | public: |
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| 341 | |
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| 342 | ///Conversion to Digraph::Arc |
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| 343 | operator const Arc&() const { |
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| 344 | return path->nth(idx); |
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| 345 | } |
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| 346 | |
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| 347 | /// Next arc |
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[209] | 348 | ArcIt& operator++() { |
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[96] | 349 | ++idx; |
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[209] | 350 | if (idx >= path->length()) idx = -1; |
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| 351 | return *this; |
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[96] | 352 | } |
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| 353 | |
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| 354 | /// Comparison operator |
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| 355 | bool operator==(const ArcIt& e) const { return idx==e.idx; } |
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| 356 | /// Comparison operator |
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| 357 | bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
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| 358 | /// Comparison operator |
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| 359 | bool operator<(const ArcIt& e) const { return idx<e.idx; } |
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| 360 | |
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| 361 | private: |
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| 362 | const SimplePath *path; |
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| 363 | int idx; |
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| 364 | }; |
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| 365 | |
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[1336] | 366 | /// \brief Gets the collection of the arcs of the path. |
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| 367 | /// |
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| 368 | /// This function can be used for iterating on the |
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| 369 | /// arcs of the path. It returns a wrapped |
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| 370 | /// ArcIt, which looks like an STL container |
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| 371 | /// (by having begin() and end()) which you can use in range-based |
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| 372 | /// for loops, STL algorithms, etc. |
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| 373 | /// For example you can write: |
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| 374 | ///\code |
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| 375 | /// for(auto a: p.arcs()) |
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| 376 | /// doSomething(a); |
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| 377 | ///\endcode |
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| 378 | LemonRangeWrapper1<ArcIt, SimplePath> arcs() const { |
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| 379 | return LemonRangeWrapper1<ArcIt, SimplePath>(*this); |
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| 380 | } |
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| 381 | |
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| 382 | |
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[96] | 383 | /// \brief Length of the path. |
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| 384 | int length() const { return data.size(); } |
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[97] | 385 | /// \brief Return true if the path is empty. |
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[96] | 386 | bool empty() const { return data.empty(); } |
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| 387 | |
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[97] | 388 | /// \brief Reset the path to an empty one. |
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[96] | 389 | void clear() { data.clear(); } |
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| 390 | |
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[1024] | 391 | /// \brief The n-th arc. |
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[96] | 392 | /// |
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[606] | 393 | /// \pre \c n is in the <tt>[0..length() - 1]</tt> range. |
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[96] | 394 | const Arc& nth(int n) const { |
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| 395 | return data[n]; |
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| 396 | } |
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| 397 | |
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[1024] | 398 | /// \brief Initializes arc iterator to point to the n-th arc. |
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[96] | 399 | ArcIt nthIt(int n) const { |
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| 400 | return ArcIt(*this, n); |
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| 401 | } |
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| 402 | |
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[97] | 403 | /// \brief The first arc of the path. |
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[96] | 404 | const Arc& front() const { |
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| 405 | return data.front(); |
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| 406 | } |
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| 407 | |
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[97] | 408 | /// \brief The last arc of the path. |
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[96] | 409 | const Arc& back() const { |
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| 410 | return data.back(); |
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| 411 | } |
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| 412 | |
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| 413 | /// \brief Add a new arc behind the current path. |
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| 414 | void addBack(const Arc& arc) { |
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| 415 | data.push_back(arc); |
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| 416 | } |
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| 417 | |
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| 418 | /// \brief Erase the last arc of the path |
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| 419 | void eraseBack() { |
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| 420 | data.pop_back(); |
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| 421 | } |
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| 422 | |
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| 423 | typedef True BuildTag; |
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| 424 | |
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| 425 | template <typename CPath> |
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| 426 | void build(const CPath& path) { |
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| 427 | int len = path.length(); |
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| 428 | data.resize(len); |
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| 429 | int index = 0; |
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| 430 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
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| 431 | data[index] = it;; |
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| 432 | ++index; |
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| 433 | } |
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| 434 | } |
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| 435 | |
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| 436 | template <typename CPath> |
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| 437 | void buildRev(const CPath& path) { |
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| 438 | int len = path.length(); |
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| 439 | data.resize(len); |
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| 440 | int index = len; |
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| 441 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
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| 442 | --index; |
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| 443 | data[index] = it;; |
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| 444 | } |
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| 445 | } |
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| 446 | |
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| 447 | protected: |
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| 448 | typedef std::vector<Arc> Container; |
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| 449 | Container data; |
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| 450 | |
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| 451 | }; |
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| 452 | |
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| 453 | /// \brief A structure for representing directed paths in a digraph. |
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| 454 | /// |
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| 455 | /// A structure for representing directed path in a digraph. |
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[606] | 456 | /// \tparam GR The digraph type in which the path is. |
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[96] | 457 | /// |
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| 458 | /// In a sense, the path can be treated as a list of arcs. The |
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[1024] | 459 | /// LEMON path type stores just this list. As a consequence it |
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[96] | 460 | /// cannot enumerate the nodes in the path and the zero length paths |
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| 461 | /// cannot store the source. |
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| 462 | /// |
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| 463 | /// This implementation is a back and front insertable and erasable |
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| 464 | /// path type. It can be indexed in O(k) time, where k is the rank |
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| 465 | /// of the arc in the path. The length can be computed in O(n) |
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| 466 | /// time. The front and back insertion and erasure is O(1) time |
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| 467 | /// and it can be splited and spliced in O(1) time. |
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[606] | 468 | template <typename GR> |
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[96] | 469 | class ListPath { |
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| 470 | public: |
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| 471 | |
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[606] | 472 | typedef GR Digraph; |
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[96] | 473 | typedef typename Digraph::Arc Arc; |
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| 474 | |
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| 475 | protected: |
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| 476 | |
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[209] | 477 | // the std::list<> is incompatible |
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[96] | 478 | // hard to create invalid iterator |
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| 479 | struct Node { |
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| 480 | Arc arc; |
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| 481 | Node *next, *prev; |
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| 482 | }; |
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| 483 | |
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| 484 | Node *first, *last; |
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| 485 | |
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| 486 | std::allocator<Node> alloc; |
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| 487 | |
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| 488 | public: |
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[209] | 489 | |
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[96] | 490 | /// \brief Default constructor |
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| 491 | /// |
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| 492 | /// Default constructor |
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| 493 | ListPath() : first(0), last(0) {} |
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| 494 | |
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[1144] | 495 | /// \brief Copy constructor |
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| 496 | /// |
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| 497 | ListPath(const ListPath& cpath) : first(0), last(0) { |
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| 498 | pathCopy(cpath, *this); |
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| 499 | } |
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| 500 | |
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[96] | 501 | /// \brief Template copy constructor |
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| 502 | /// |
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| 503 | /// This path can be initialized with any other path type. It just |
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| 504 | /// makes a copy of the given path. |
---|
| 505 | template <typename CPath> |
---|
| 506 | ListPath(const CPath& cpath) : first(0), last(0) { |
---|
[551] | 507 | pathCopy(cpath, *this); |
---|
[96] | 508 | } |
---|
| 509 | |
---|
| 510 | /// \brief Destructor of the path |
---|
| 511 | /// |
---|
| 512 | /// Destructor of the path |
---|
| 513 | ~ListPath() { |
---|
| 514 | clear(); |
---|
| 515 | } |
---|
| 516 | |
---|
[1144] | 517 | /// \brief Copy assignment |
---|
| 518 | /// |
---|
| 519 | ListPath& operator=(const ListPath& cpath) { |
---|
| 520 | pathCopy(cpath, *this); |
---|
| 521 | return *this; |
---|
| 522 | } |
---|
| 523 | |
---|
[96] | 524 | /// \brief Template copy assignment |
---|
| 525 | /// |
---|
| 526 | /// This path can be initialized with any other path type. It just |
---|
| 527 | /// makes a copy of the given path. |
---|
| 528 | template <typename CPath> |
---|
| 529 | ListPath& operator=(const CPath& cpath) { |
---|
[551] | 530 | pathCopy(cpath, *this); |
---|
[96] | 531 | return *this; |
---|
| 532 | } |
---|
| 533 | |
---|
| 534 | /// \brief Iterator class to iterate on the arcs of the paths |
---|
| 535 | /// |
---|
| 536 | /// This class is used to iterate on the arcs of the paths |
---|
| 537 | /// |
---|
| 538 | /// Of course it converts to Digraph::Arc |
---|
| 539 | class ArcIt { |
---|
| 540 | friend class ListPath; |
---|
| 541 | public: |
---|
| 542 | /// Default constructor |
---|
| 543 | ArcIt() {} |
---|
| 544 | /// Invalid constructor |
---|
| 545 | ArcIt(Invalid) : path(0), node(0) {} |
---|
| 546 | /// \brief Initializate the constructor to the first arc of path |
---|
[209] | 547 | ArcIt(const ListPath &_path) |
---|
[96] | 548 | : path(&_path), node(_path.first) {} |
---|
| 549 | |
---|
| 550 | protected: |
---|
| 551 | |
---|
[209] | 552 | ArcIt(const ListPath &_path, Node *_node) |
---|
[96] | 553 | : path(&_path), node(_node) {} |
---|
| 554 | |
---|
| 555 | |
---|
| 556 | public: |
---|
| 557 | |
---|
| 558 | ///Conversion to Digraph::Arc |
---|
| 559 | operator const Arc&() const { |
---|
| 560 | return node->arc; |
---|
| 561 | } |
---|
| 562 | |
---|
| 563 | /// Next arc |
---|
[209] | 564 | ArcIt& operator++() { |
---|
[96] | 565 | node = node->next; |
---|
[209] | 566 | return *this; |
---|
[96] | 567 | } |
---|
| 568 | |
---|
| 569 | /// Comparison operator |
---|
| 570 | bool operator==(const ArcIt& e) const { return node==e.node; } |
---|
| 571 | /// Comparison operator |
---|
| 572 | bool operator!=(const ArcIt& e) const { return node!=e.node; } |
---|
| 573 | /// Comparison operator |
---|
| 574 | bool operator<(const ArcIt& e) const { return node<e.node; } |
---|
| 575 | |
---|
| 576 | private: |
---|
| 577 | const ListPath *path; |
---|
| 578 | Node *node; |
---|
| 579 | }; |
---|
| 580 | |
---|
[1336] | 581 | /// \brief Gets the collection of the arcs of the path. |
---|
| 582 | /// |
---|
| 583 | /// This function can be used for iterating on the |
---|
| 584 | /// arcs of the path. It returns a wrapped |
---|
| 585 | /// ArcIt, which looks like an STL container |
---|
| 586 | /// (by having begin() and end()) which you can use in range-based |
---|
| 587 | /// for loops, STL algorithms, etc. |
---|
| 588 | /// For example you can write: |
---|
| 589 | ///\code |
---|
| 590 | /// for(auto a: p.arcs()) |
---|
| 591 | /// doSomething(a); |
---|
| 592 | ///\endcode |
---|
| 593 | LemonRangeWrapper1<ArcIt, ListPath> arcs() const { |
---|
| 594 | return LemonRangeWrapper1<ArcIt, ListPath>(*this); |
---|
| 595 | } |
---|
| 596 | |
---|
| 597 | |
---|
[1024] | 598 | /// \brief The n-th arc. |
---|
[96] | 599 | /// |
---|
[1024] | 600 | /// This function looks for the n-th arc in O(n) time. |
---|
[606] | 601 | /// \pre \c n is in the <tt>[0..length() - 1]</tt> range. |
---|
[96] | 602 | const Arc& nth(int n) const { |
---|
| 603 | Node *node = first; |
---|
| 604 | for (int i = 0; i < n; ++i) { |
---|
| 605 | node = node->next; |
---|
| 606 | } |
---|
| 607 | return node->arc; |
---|
| 608 | } |
---|
| 609 | |
---|
[1024] | 610 | /// \brief Initializes arc iterator to point to the n-th arc. |
---|
[96] | 611 | ArcIt nthIt(int n) const { |
---|
| 612 | Node *node = first; |
---|
| 613 | for (int i = 0; i < n; ++i) { |
---|
| 614 | node = node->next; |
---|
| 615 | } |
---|
| 616 | return ArcIt(*this, node); |
---|
| 617 | } |
---|
| 618 | |
---|
| 619 | /// \brief Length of the path. |
---|
| 620 | int length() const { |
---|
| 621 | int len = 0; |
---|
| 622 | Node *node = first; |
---|
| 623 | while (node != 0) { |
---|
| 624 | node = node->next; |
---|
| 625 | ++len; |
---|
| 626 | } |
---|
| 627 | return len; |
---|
| 628 | } |
---|
| 629 | |
---|
[97] | 630 | /// \brief Return true if the path is empty. |
---|
[96] | 631 | bool empty() const { return first == 0; } |
---|
| 632 | |
---|
[97] | 633 | /// \brief Reset the path to an empty one. |
---|
[96] | 634 | void clear() { |
---|
| 635 | while (first != 0) { |
---|
| 636 | last = first->next; |
---|
| 637 | alloc.destroy(first); |
---|
| 638 | alloc.deallocate(first, 1); |
---|
| 639 | first = last; |
---|
| 640 | } |
---|
| 641 | } |
---|
| 642 | |
---|
[97] | 643 | /// \brief The first arc of the path |
---|
[96] | 644 | const Arc& front() const { |
---|
| 645 | return first->arc; |
---|
| 646 | } |
---|
| 647 | |
---|
| 648 | /// \brief Add a new arc before the current path |
---|
| 649 | void addFront(const Arc& arc) { |
---|
| 650 | Node *node = alloc.allocate(1); |
---|
| 651 | alloc.construct(node, Node()); |
---|
| 652 | node->prev = 0; |
---|
| 653 | node->next = first; |
---|
| 654 | node->arc = arc; |
---|
| 655 | if (first) { |
---|
| 656 | first->prev = node; |
---|
| 657 | first = node; |
---|
| 658 | } else { |
---|
| 659 | first = last = node; |
---|
| 660 | } |
---|
| 661 | } |
---|
| 662 | |
---|
| 663 | /// \brief Erase the first arc of the path |
---|
| 664 | void eraseFront() { |
---|
| 665 | Node *node = first; |
---|
| 666 | first = first->next; |
---|
| 667 | if (first) { |
---|
| 668 | first->prev = 0; |
---|
| 669 | } else { |
---|
| 670 | last = 0; |
---|
| 671 | } |
---|
| 672 | alloc.destroy(node); |
---|
| 673 | alloc.deallocate(node, 1); |
---|
| 674 | } |
---|
| 675 | |
---|
[97] | 676 | /// \brief The last arc of the path. |
---|
[96] | 677 | const Arc& back() const { |
---|
| 678 | return last->arc; |
---|
| 679 | } |
---|
| 680 | |
---|
| 681 | /// \brief Add a new arc behind the current path. |
---|
| 682 | void addBack(const Arc& arc) { |
---|
| 683 | Node *node = alloc.allocate(1); |
---|
| 684 | alloc.construct(node, Node()); |
---|
| 685 | node->next = 0; |
---|
| 686 | node->prev = last; |
---|
| 687 | node->arc = arc; |
---|
| 688 | if (last) { |
---|
| 689 | last->next = node; |
---|
| 690 | last = node; |
---|
| 691 | } else { |
---|
| 692 | last = first = node; |
---|
| 693 | } |
---|
| 694 | } |
---|
| 695 | |
---|
| 696 | /// \brief Erase the last arc of the path |
---|
| 697 | void eraseBack() { |
---|
| 698 | Node *node = last; |
---|
| 699 | last = last->prev; |
---|
| 700 | if (last) { |
---|
| 701 | last->next = 0; |
---|
| 702 | } else { |
---|
| 703 | first = 0; |
---|
| 704 | } |
---|
| 705 | alloc.destroy(node); |
---|
| 706 | alloc.deallocate(node, 1); |
---|
| 707 | } |
---|
| 708 | |
---|
[97] | 709 | /// \brief Splice a path to the back of the current path. |
---|
[96] | 710 | /// |
---|
[97] | 711 | /// It splices \c tpath to the back of the current path and \c |
---|
[96] | 712 | /// tpath becomes empty. The time complexity of this function is |
---|
| 713 | /// O(1). |
---|
| 714 | void spliceBack(ListPath& tpath) { |
---|
| 715 | if (first) { |
---|
| 716 | if (tpath.first) { |
---|
| 717 | last->next = tpath.first; |
---|
| 718 | tpath.first->prev = last; |
---|
| 719 | last = tpath.last; |
---|
| 720 | } |
---|
| 721 | } else { |
---|
| 722 | first = tpath.first; |
---|
| 723 | last = tpath.last; |
---|
| 724 | } |
---|
| 725 | tpath.first = tpath.last = 0; |
---|
| 726 | } |
---|
| 727 | |
---|
[97] | 728 | /// \brief Splice a path to the front of the current path. |
---|
[96] | 729 | /// |
---|
[97] | 730 | /// It splices \c tpath before the current path and \c tpath |
---|
[96] | 731 | /// becomes empty. The time complexity of this function |
---|
| 732 | /// is O(1). |
---|
| 733 | void spliceFront(ListPath& tpath) { |
---|
| 734 | if (first) { |
---|
| 735 | if (tpath.first) { |
---|
| 736 | first->prev = tpath.last; |
---|
| 737 | tpath.last->next = first; |
---|
| 738 | first = tpath.first; |
---|
| 739 | } |
---|
| 740 | } else { |
---|
| 741 | first = tpath.first; |
---|
| 742 | last = tpath.last; |
---|
| 743 | } |
---|
| 744 | tpath.first = tpath.last = 0; |
---|
| 745 | } |
---|
| 746 | |
---|
[97] | 747 | /// \brief Splice a path into the current path. |
---|
[96] | 748 | /// |
---|
| 749 | /// It splices the \c tpath into the current path before the |
---|
| 750 | /// position of \c it iterator and \c tpath becomes empty. The |
---|
[97] | 751 | /// time complexity of this function is O(1). If the \c it is |
---|
| 752 | /// \c INVALID then it will splice behind the current path. |
---|
[96] | 753 | void splice(ArcIt it, ListPath& tpath) { |
---|
| 754 | if (it.node) { |
---|
| 755 | if (tpath.first) { |
---|
| 756 | tpath.first->prev = it.node->prev; |
---|
| 757 | if (it.node->prev) { |
---|
| 758 | it.node->prev->next = tpath.first; |
---|
| 759 | } else { |
---|
| 760 | first = tpath.first; |
---|
| 761 | } |
---|
| 762 | it.node->prev = tpath.last; |
---|
| 763 | tpath.last->next = it.node; |
---|
| 764 | } |
---|
| 765 | } else { |
---|
| 766 | if (first) { |
---|
| 767 | if (tpath.first) { |
---|
| 768 | last->next = tpath.first; |
---|
| 769 | tpath.first->prev = last; |
---|
| 770 | last = tpath.last; |
---|
| 771 | } |
---|
| 772 | } else { |
---|
| 773 | first = tpath.first; |
---|
| 774 | last = tpath.last; |
---|
| 775 | } |
---|
| 776 | } |
---|
| 777 | tpath.first = tpath.last = 0; |
---|
| 778 | } |
---|
| 779 | |
---|
[97] | 780 | /// \brief Split the current path. |
---|
[96] | 781 | /// |
---|
[97] | 782 | /// It splits the current path into two parts. The part before |
---|
| 783 | /// the iterator \c it will remain in the current path and the part |
---|
| 784 | /// starting with |
---|
| 785 | /// \c it will put into \c tpath. If \c tpath have arcs |
---|
| 786 | /// before the operation they are removed first. The time |
---|
| 787 | /// complexity of this function is O(1) plus the the time of emtying |
---|
| 788 | /// \c tpath. If \c it is \c INVALID then it just clears \c tpath |
---|
[96] | 789 | void split(ArcIt it, ListPath& tpath) { |
---|
| 790 | tpath.clear(); |
---|
| 791 | if (it.node) { |
---|
| 792 | tpath.first = it.node; |
---|
| 793 | tpath.last = last; |
---|
| 794 | if (it.node->prev) { |
---|
| 795 | last = it.node->prev; |
---|
| 796 | last->next = 0; |
---|
| 797 | } else { |
---|
| 798 | first = last = 0; |
---|
| 799 | } |
---|
| 800 | it.node->prev = 0; |
---|
| 801 | } |
---|
| 802 | } |
---|
| 803 | |
---|
| 804 | |
---|
| 805 | typedef True BuildTag; |
---|
| 806 | |
---|
| 807 | template <typename CPath> |
---|
| 808 | void build(const CPath& path) { |
---|
| 809 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
---|
| 810 | addBack(it); |
---|
| 811 | } |
---|
| 812 | } |
---|
| 813 | |
---|
| 814 | template <typename CPath> |
---|
| 815 | void buildRev(const CPath& path) { |
---|
| 816 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
---|
| 817 | addFront(it); |
---|
| 818 | } |
---|
| 819 | } |
---|
| 820 | |
---|
| 821 | }; |
---|
| 822 | |
---|
| 823 | /// \brief A structure for representing directed paths in a digraph. |
---|
| 824 | /// |
---|
| 825 | /// A structure for representing directed path in a digraph. |
---|
[606] | 826 | /// \tparam GR The digraph type in which the path is. |
---|
[96] | 827 | /// |
---|
| 828 | /// In a sense, the path can be treated as a list of arcs. The |
---|
[1024] | 829 | /// LEMON path type stores just this list. As a consequence it |
---|
[97] | 830 | /// cannot enumerate the nodes in the path and the source node of |
---|
| 831 | /// a zero length path is undefined. |
---|
[96] | 832 | /// |
---|
[97] | 833 | /// This implementation is completly static, i.e. it can be copy constucted |
---|
| 834 | /// or copy assigned from another path, but otherwise it cannot be |
---|
| 835 | /// modified. |
---|
| 836 | /// |
---|
| 837 | /// Being the the most memory efficient path type in LEMON, |
---|
| 838 | /// it is intented to be |
---|
| 839 | /// used when you want to store a large number of paths. |
---|
[606] | 840 | template <typename GR> |
---|
[96] | 841 | class StaticPath { |
---|
| 842 | public: |
---|
| 843 | |
---|
[606] | 844 | typedef GR Digraph; |
---|
[96] | 845 | typedef typename Digraph::Arc Arc; |
---|
| 846 | |
---|
| 847 | /// \brief Default constructor |
---|
| 848 | /// |
---|
| 849 | /// Default constructor |
---|
[1336] | 850 | StaticPath() : len(0), _arcs(0) {} |
---|
[209] | 851 | |
---|
[1144] | 852 | /// \brief Copy constructor |
---|
| 853 | /// |
---|
[1336] | 854 | StaticPath(const StaticPath& cpath) : _arcs(0) { |
---|
[1144] | 855 | pathCopy(cpath, *this); |
---|
| 856 | } |
---|
| 857 | |
---|
[96] | 858 | /// \brief Template copy constructor |
---|
| 859 | /// |
---|
[97] | 860 | /// This path can be initialized from any other path type. |
---|
[96] | 861 | template <typename CPath> |
---|
[1336] | 862 | StaticPath(const CPath& cpath) : _arcs(0) { |
---|
[551] | 863 | pathCopy(cpath, *this); |
---|
[96] | 864 | } |
---|
| 865 | |
---|
| 866 | /// \brief Destructor of the path |
---|
| 867 | /// |
---|
| 868 | /// Destructor of the path |
---|
| 869 | ~StaticPath() { |
---|
[1336] | 870 | if (_arcs) delete[] _arcs; |
---|
[96] | 871 | } |
---|
| 872 | |
---|
[1144] | 873 | /// \brief Copy assignment |
---|
| 874 | /// |
---|
| 875 | StaticPath& operator=(const StaticPath& cpath) { |
---|
| 876 | pathCopy(cpath, *this); |
---|
| 877 | return *this; |
---|
| 878 | } |
---|
| 879 | |
---|
[96] | 880 | /// \brief Template copy assignment |
---|
| 881 | /// |
---|
[97] | 882 | /// This path can be made equal to any other path type. It simply |
---|
[96] | 883 | /// makes a copy of the given path. |
---|
| 884 | template <typename CPath> |
---|
| 885 | StaticPath& operator=(const CPath& cpath) { |
---|
[551] | 886 | pathCopy(cpath, *this); |
---|
[96] | 887 | return *this; |
---|
| 888 | } |
---|
| 889 | |
---|
| 890 | /// \brief Iterator class to iterate on the arcs of the paths |
---|
| 891 | /// |
---|
| 892 | /// This class is used to iterate on the arcs of the paths |
---|
| 893 | /// |
---|
| 894 | /// Of course it converts to Digraph::Arc |
---|
| 895 | class ArcIt { |
---|
| 896 | friend class StaticPath; |
---|
| 897 | public: |
---|
| 898 | /// Default constructor |
---|
| 899 | ArcIt() {} |
---|
| 900 | /// Invalid constructor |
---|
| 901 | ArcIt(Invalid) : path(0), idx(-1) {} |
---|
| 902 | /// Initializate the constructor to the first arc of path |
---|
[209] | 903 | ArcIt(const StaticPath &_path) |
---|
[96] | 904 | : path(&_path), idx(_path.empty() ? -1 : 0) {} |
---|
| 905 | |
---|
| 906 | private: |
---|
| 907 | |
---|
| 908 | /// Constructor with starting point |
---|
[209] | 909 | ArcIt(const StaticPath &_path, int _idx) |
---|
[96] | 910 | : idx(_idx), path(&_path) {} |
---|
| 911 | |
---|
| 912 | public: |
---|
| 913 | |
---|
| 914 | ///Conversion to Digraph::Arc |
---|
| 915 | operator const Arc&() const { |
---|
| 916 | return path->nth(idx); |
---|
| 917 | } |
---|
| 918 | |
---|
| 919 | /// Next arc |
---|
[209] | 920 | ArcIt& operator++() { |
---|
[96] | 921 | ++idx; |
---|
[209] | 922 | if (idx >= path->length()) idx = -1; |
---|
| 923 | return *this; |
---|
[96] | 924 | } |
---|
| 925 | |
---|
| 926 | /// Comparison operator |
---|
| 927 | bool operator==(const ArcIt& e) const { return idx==e.idx; } |
---|
| 928 | /// Comparison operator |
---|
| 929 | bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
---|
| 930 | /// Comparison operator |
---|
| 931 | bool operator<(const ArcIt& e) const { return idx<e.idx; } |
---|
| 932 | |
---|
| 933 | private: |
---|
| 934 | const StaticPath *path; |
---|
| 935 | int idx; |
---|
| 936 | }; |
---|
[1336] | 937 | |
---|
| 938 | /// \brief Gets the collection of the arcs of the path. |
---|
| 939 | /// |
---|
| 940 | /// This function can be used for iterating on the |
---|
| 941 | /// arcs of the path. It returns a wrapped |
---|
| 942 | /// ArcIt, which looks like an STL container |
---|
| 943 | /// (by having begin() and end()) which you can use in range-based |
---|
| 944 | /// for loops, STL algorithms, etc. |
---|
| 945 | /// For example you can write: |
---|
| 946 | ///\code |
---|
| 947 | /// for(auto a: p.arcs()) |
---|
| 948 | /// doSomething(a); |
---|
| 949 | ///\endcode |
---|
| 950 | LemonRangeWrapper1<ArcIt, StaticPath> arcs() const { |
---|
| 951 | return LemonRangeWrapper1<ArcIt, StaticPath>(*this); |
---|
| 952 | } |
---|
| 953 | |
---|
[96] | 954 | |
---|
[1024] | 955 | /// \brief The n-th arc. |
---|
[96] | 956 | /// |
---|
[606] | 957 | /// \pre \c n is in the <tt>[0..length() - 1]</tt> range. |
---|
[96] | 958 | const Arc& nth(int n) const { |
---|
[1336] | 959 | return _arcs[n]; |
---|
[96] | 960 | } |
---|
| 961 | |
---|
[1024] | 962 | /// \brief The arc iterator pointing to the n-th arc. |
---|
[96] | 963 | ArcIt nthIt(int n) const { |
---|
| 964 | return ArcIt(*this, n); |
---|
| 965 | } |
---|
| 966 | |
---|
[97] | 967 | /// \brief The length of the path. |
---|
[96] | 968 | int length() const { return len; } |
---|
| 969 | |
---|
[97] | 970 | /// \brief Return true when the path is empty. |
---|
[96] | 971 | int empty() const { return len == 0; } |
---|
| 972 | |
---|
[313] | 973 | /// \brief Erase all arcs in the digraph. |
---|
[96] | 974 | void clear() { |
---|
| 975 | len = 0; |
---|
[1336] | 976 | if (_arcs) delete[] _arcs; |
---|
| 977 | _arcs = 0; |
---|
[96] | 978 | } |
---|
| 979 | |
---|
[97] | 980 | /// \brief The first arc of the path. |
---|
[96] | 981 | const Arc& front() const { |
---|
[1336] | 982 | return _arcs[0]; |
---|
[96] | 983 | } |
---|
| 984 | |
---|
[97] | 985 | /// \brief The last arc of the path. |
---|
[96] | 986 | const Arc& back() const { |
---|
[1336] | 987 | return _arcs[len - 1]; |
---|
[96] | 988 | } |
---|
| 989 | |
---|
| 990 | |
---|
| 991 | typedef True BuildTag; |
---|
| 992 | |
---|
| 993 | template <typename CPath> |
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| 994 | void build(const CPath& path) { |
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| 995 | len = path.length(); |
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[1336] | 996 | _arcs = new Arc[len]; |
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[96] | 997 | int index = 0; |
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| 998 | for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
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[1336] | 999 | _arcs[index] = it; |
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[96] | 1000 | ++index; |
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| 1001 | } |
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| 1002 | } |
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| 1003 | |
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| 1004 | template <typename CPath> |
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| 1005 | void buildRev(const CPath& path) { |
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| 1006 | len = path.length(); |
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[1336] | 1007 | _arcs = new Arc[len]; |
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[96] | 1008 | int index = len; |
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| 1009 | for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
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| 1010 | --index; |
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[1336] | 1011 | _arcs[index] = it; |
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[96] | 1012 | } |
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| 1013 | } |
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| 1014 | |
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| 1015 | private: |
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| 1016 | int len; |
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[1336] | 1017 | Arc* _arcs; |
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[96] | 1018 | }; |
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| 1019 | |
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[98] | 1020 | /////////////////////////////////////////////////////////////////////// |
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| 1021 | // Additional utilities |
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| 1022 | /////////////////////////////////////////////////////////////////////// |
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| 1023 | |
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| 1024 | namespace _path_bits { |
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| 1025 | |
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| 1026 | template <typename Path, typename Enable = void> |
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[144] | 1027 | struct RevPathTagIndicator { |
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[98] | 1028 | static const bool value = false; |
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| 1029 | }; |
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| 1030 | |
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[144] | 1031 | template <typename Path> |
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| 1032 | struct RevPathTagIndicator< |
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[209] | 1033 | Path, |
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[144] | 1034 | typename enable_if<typename Path::RevPathTag, void>::type |
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| 1035 | > { |
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| 1036 | static const bool value = true; |
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| 1037 | }; |
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| 1038 | |
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| 1039 | template <typename Path, typename Enable = void> |
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| 1040 | struct BuildTagIndicator { |
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| 1041 | static const bool value = false; |
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| 1042 | }; |
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| 1043 | |
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| 1044 | template <typename Path> |
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| 1045 | struct BuildTagIndicator< |
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[209] | 1046 | Path, |
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[144] | 1047 | typename enable_if<typename Path::BuildTag, void>::type |
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[98] | 1048 | > { |
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| 1049 | static const bool value = true; |
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| 1050 | }; |
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| 1051 | |
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[551] | 1052 | template <typename From, typename To, |
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| 1053 | bool buildEnable = BuildTagIndicator<To>::value> |
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[517] | 1054 | struct PathCopySelectorForward { |
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[551] | 1055 | static void copy(const From& from, To& to) { |
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| 1056 | to.clear(); |
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| 1057 | for (typename From::ArcIt it(from); it != INVALID; ++it) { |
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| 1058 | to.addBack(it); |
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[98] | 1059 | } |
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| 1060 | } |
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| 1061 | }; |
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| 1062 | |
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[551] | 1063 | template <typename From, typename To> |
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| 1064 | struct PathCopySelectorForward<From, To, true> { |
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| 1065 | static void copy(const From& from, To& to) { |
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| 1066 | to.clear(); |
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| 1067 | to.build(from); |
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[517] | 1068 | } |
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| 1069 | }; |
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| 1070 | |
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[551] | 1071 | template <typename From, typename To, |
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| 1072 | bool buildEnable = BuildTagIndicator<To>::value> |
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[517] | 1073 | struct PathCopySelectorBackward { |
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[551] | 1074 | static void copy(const From& from, To& to) { |
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| 1075 | to.clear(); |
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| 1076 | for (typename From::RevArcIt it(from); it != INVALID; ++it) { |
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| 1077 | to.addFront(it); |
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[98] | 1078 | } |
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| 1079 | } |
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| 1080 | }; |
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| 1081 | |
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[551] | 1082 | template <typename From, typename To> |
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| 1083 | struct PathCopySelectorBackward<From, To, true> { |
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| 1084 | static void copy(const From& from, To& to) { |
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| 1085 | to.clear(); |
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| 1086 | to.buildRev(from); |
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[98] | 1087 | } |
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| 1088 | }; |
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| 1089 | |
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[956] | 1090 | |
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[551] | 1091 | template <typename From, typename To, |
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| 1092 | bool revEnable = RevPathTagIndicator<From>::value> |
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[517] | 1093 | struct PathCopySelector { |
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[551] | 1094 | static void copy(const From& from, To& to) { |
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| 1095 | PathCopySelectorForward<From, To>::copy(from, to); |
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[956] | 1096 | } |
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[517] | 1097 | }; |
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| 1098 | |
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[551] | 1099 | template <typename From, typename To> |
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| 1100 | struct PathCopySelector<From, To, true> { |
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| 1101 | static void copy(const From& from, To& to) { |
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| 1102 | PathCopySelectorBackward<From, To>::copy(from, to); |
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[956] | 1103 | } |
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[517] | 1104 | }; |
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| 1105 | |
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[98] | 1106 | } |
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| 1107 | |
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| 1108 | |
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| 1109 | /// \brief Make a copy of a path. |
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| 1110 | /// |
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[551] | 1111 | /// This function makes a copy of a path. |
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| 1112 | template <typename From, typename To> |
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| 1113 | void pathCopy(const From& from, To& to) { |
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| 1114 | checkConcept<concepts::PathDumper<typename From::Digraph>, From>(); |
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| 1115 | _path_bits::PathCopySelector<From, To>::copy(from, to); |
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| 1116 | } |
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| 1117 | |
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| 1118 | /// \brief Deprecated version of \ref pathCopy(). |
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| 1119 | /// |
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| 1120 | /// Deprecated version of \ref pathCopy() (only for reverse compatibility). |
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| 1121 | template <typename To, typename From> |
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| 1122 | void copyPath(To& to, const From& from) { |
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| 1123 | pathCopy(from, to); |
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[98] | 1124 | } |
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| 1125 | |
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| 1126 | /// \brief Check the consistency of a path. |
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| 1127 | /// |
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| 1128 | /// This function checks that the target of each arc is the same |
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[209] | 1129 | /// as the source of the next one. |
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| 1130 | /// |
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[98] | 1131 | template <typename Digraph, typename Path> |
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| 1132 | bool checkPath(const Digraph& digraph, const Path& path) { |
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| 1133 | typename Path::ArcIt it(path); |
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| 1134 | if (it == INVALID) return true; |
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| 1135 | typename Digraph::Node node = digraph.target(it); |
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| 1136 | ++it; |
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| 1137 | while (it != INVALID) { |
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| 1138 | if (digraph.source(it) != node) return false; |
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| 1139 | node = digraph.target(it); |
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| 1140 | ++it; |
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| 1141 | } |
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| 1142 | return true; |
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| 1143 | } |
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| 1144 | |
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| 1145 | /// \brief The source of a path |
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| 1146 | /// |
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[548] | 1147 | /// This function returns the source node of the given path. |
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| 1148 | /// If the path is empty, then it returns \c INVALID. |
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[98] | 1149 | template <typename Digraph, typename Path> |
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| 1150 | typename Digraph::Node pathSource(const Digraph& digraph, const Path& path) { |
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[548] | 1151 | return path.empty() ? INVALID : digraph.source(path.front()); |
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[98] | 1152 | } |
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| 1153 | |
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| 1154 | /// \brief The target of a path |
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| 1155 | /// |
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[548] | 1156 | /// This function returns the target node of the given path. |
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| 1157 | /// If the path is empty, then it returns \c INVALID. |
---|
[98] | 1158 | template <typename Digraph, typename Path> |
---|
| 1159 | typename Digraph::Node pathTarget(const Digraph& digraph, const Path& path) { |
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[548] | 1160 | return path.empty() ? INVALID : digraph.target(path.back()); |
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[98] | 1161 | } |
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| 1162 | |
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| 1163 | /// \brief Class which helps to iterate through the nodes of a path |
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| 1164 | /// |
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| 1165 | /// In a sense, the path can be treated as a list of arcs. The |
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[1024] | 1166 | /// LEMON path type stores only this list. As a consequence, it |
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[98] | 1167 | /// cannot enumerate the nodes in the path and the zero length paths |
---|
| 1168 | /// cannot have a source node. |
---|
| 1169 | /// |
---|
| 1170 | /// This class implements the node iterator of a path structure. To |
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| 1171 | /// provide this feature, the underlying digraph should be passed to |
---|
| 1172 | /// the constructor of the iterator. |
---|
| 1173 | template <typename Path> |
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| 1174 | class PathNodeIt { |
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| 1175 | private: |
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| 1176 | const typename Path::Digraph *_digraph; |
---|
| 1177 | typename Path::ArcIt _it; |
---|
| 1178 | typename Path::Digraph::Node _nd; |
---|
| 1179 | |
---|
| 1180 | public: |
---|
| 1181 | |
---|
| 1182 | typedef typename Path::Digraph Digraph; |
---|
| 1183 | typedef typename Digraph::Node Node; |
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[209] | 1184 | |
---|
[98] | 1185 | /// Default constructor |
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| 1186 | PathNodeIt() {} |
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| 1187 | /// Invalid constructor |
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[209] | 1188 | PathNodeIt(Invalid) |
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[98] | 1189 | : _digraph(0), _it(INVALID), _nd(INVALID) {} |
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| 1190 | /// Constructor |
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[209] | 1191 | PathNodeIt(const Digraph& digraph, const Path& path) |
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[98] | 1192 | : _digraph(&digraph), _it(path) { |
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| 1193 | _nd = (_it != INVALID ? _digraph->source(_it) : INVALID); |
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| 1194 | } |
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| 1195 | /// Constructor |
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[209] | 1196 | PathNodeIt(const Digraph& digraph, const Path& path, const Node& src) |
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[98] | 1197 | : _digraph(&digraph), _it(path), _nd(src) {} |
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| 1198 | |
---|
| 1199 | ///Conversion to Digraph::Node |
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| 1200 | operator Node() const { |
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| 1201 | return _nd; |
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| 1202 | } |
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| 1203 | |
---|
| 1204 | /// Next node |
---|
| 1205 | PathNodeIt& operator++() { |
---|
| 1206 | if (_it == INVALID) _nd = INVALID; |
---|
| 1207 | else { |
---|
[209] | 1208 | _nd = _digraph->target(_it); |
---|
| 1209 | ++_it; |
---|
[98] | 1210 | } |
---|
| 1211 | return *this; |
---|
| 1212 | } |
---|
| 1213 | |
---|
| 1214 | /// Comparison operator |
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[209] | 1215 | bool operator==(const PathNodeIt& n) const { |
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| 1216 | return _it == n._it && _nd == n._nd; |
---|
[98] | 1217 | } |
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| 1218 | /// Comparison operator |
---|
[209] | 1219 | bool operator!=(const PathNodeIt& n) const { |
---|
| 1220 | return _it != n._it || _nd != n._nd; |
---|
[98] | 1221 | } |
---|
| 1222 | /// Comparison operator |
---|
[209] | 1223 | bool operator<(const PathNodeIt& n) const { |
---|
[98] | 1224 | return (_it < n._it && _nd != INVALID); |
---|
| 1225 | } |
---|
[209] | 1226 | |
---|
[98] | 1227 | }; |
---|
[209] | 1228 | |
---|
[1336] | 1229 | /// \brief Gets the collection of the nodes of the path. |
---|
| 1230 | /// |
---|
| 1231 | /// This function can be used for iterating on the |
---|
| 1232 | /// nodes of the path. It returns a wrapped |
---|
| 1233 | /// PathNodeIt, which looks like an STL container |
---|
| 1234 | /// (by having begin() and end()) which you can use in range-based |
---|
| 1235 | /// for loops, STL algorithms, etc. |
---|
| 1236 | /// For example you can write: |
---|
| 1237 | ///\code |
---|
| 1238 | /// for(auto u: pathNodes(g,p)) |
---|
| 1239 | /// doSomething(u); |
---|
| 1240 | ///\endcode |
---|
| 1241 | template<typename Path> |
---|
| 1242 | LemonRangeWrapper2<PathNodeIt<Path>, typename Path::Digraph, Path> |
---|
| 1243 | pathNodes(const typename Path::Digraph &g, const Path &p) { |
---|
| 1244 | return |
---|
| 1245 | LemonRangeWrapper2<PathNodeIt<Path>, typename Path::Digraph, Path>(g,p); |
---|
| 1246 | } |
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| 1247 | |
---|
[96] | 1248 | ///@} |
---|
| 1249 | |
---|
| 1250 | } // namespace lemon |
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| 1251 | |
---|
| 1252 | #endif // LEMON_PATH_H |
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