[906] | 1 | /* -*- C++ -*- |
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| 2 | * |
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[1956] | 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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| 5 | * Copyright (C) 2003-2006 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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[1359] | 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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[906] | 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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[819] | 18 | |
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| 19 | |
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| 20 | ///\ingroup paths |
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| 21 | ///\file |
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| 22 | ///\brief Classes for representing paths in graphs. |
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[1151] | 23 | /// |
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| 24 | ///\todo Iterators have obsolete style |
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[819] | 25 | |
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[921] | 26 | #ifndef LEMON_PATH_H |
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| 27 | #define LEMON_PATH_H |
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[819] | 28 | |
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| 29 | #include <deque> |
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| 30 | #include <vector> |
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| 31 | #include <algorithm> |
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| 32 | |
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[1993] | 33 | #include <lemon/bits/invalid.h> |
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[819] | 34 | |
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[921] | 35 | namespace lemon { |
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[819] | 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 graph. |
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| 42 | //! |
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| 43 | //! A structure for representing directed path in a graph. |
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| 44 | //! \param Graph The graph type in which the path is. |
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| 45 | //! \param DM DebugMode, defaults to DefaultDebugMode. |
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[837] | 46 | //! |
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[819] | 47 | //! In a sense, the path can be treated as a graph, for is has \c NodeIt |
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| 48 | //! and \c EdgeIt with the same usage. These types converts to the \c Node |
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| 49 | //! and \c Edge of the original graph. |
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| 50 | //! |
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| 51 | //! \todo Thoroughfully check all the range and consistency tests. |
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[831] | 52 | template<typename Graph> |
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[819] | 53 | class DirPath { |
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| 54 | public: |
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| 55 | /// Edge type of the underlying graph. |
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[837] | 56 | typedef typename Graph::Edge GraphEdge; |
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[819] | 57 | /// Node type of the underlying graph. |
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| 58 | typedef typename Graph::Node GraphNode; |
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| 59 | class NodeIt; |
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| 60 | class EdgeIt; |
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| 61 | |
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| 62 | protected: |
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| 63 | const Graph *gr; |
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| 64 | typedef std::vector<GraphEdge> Container; |
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| 65 | Container edges; |
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| 66 | |
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| 67 | public: |
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| 68 | |
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| 69 | /// \param _G The graph in which the path is. |
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| 70 | /// |
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| 71 | DirPath(const Graph &_G) : gr(&_G) {} |
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| 72 | |
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| 73 | /// \brief Subpath constructor. |
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| 74 | /// |
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| 75 | /// Subpath defined by two nodes. |
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| 76 | /// \warning It is an error if the two edges are not in order! |
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| 77 | DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b) { |
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| 78 | gr = P.gr; |
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| 79 | edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx); |
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| 80 | } |
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| 81 | |
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| 82 | /// \brief Subpath constructor. |
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| 83 | /// |
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| 84 | /// Subpath defined by two edges. Contains edges in [a,b) |
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| 85 | /// \warning It is an error if the two edges are not in order! |
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| 86 | DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b) { |
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| 87 | gr = P.gr; |
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| 88 | edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx); |
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| 89 | } |
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| 90 | |
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| 91 | /// Length of the path. |
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[1282] | 92 | int length() const { return edges.size(); } |
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[819] | 93 | /// Returns whether the path is empty. |
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| 94 | bool empty() const { return edges.empty(); } |
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| 95 | |
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| 96 | /// Resets the path to an empty path. |
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| 97 | void clear() { edges.clear(); } |
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| 98 | |
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| 99 | /// \brief Starting point of the path. |
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| 100 | /// |
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| 101 | /// Starting point of the path. |
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| 102 | /// Returns INVALID if the path is empty. |
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[986] | 103 | GraphNode source() const { |
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| 104 | return empty() ? INVALID : gr->source(edges[0]); |
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[819] | 105 | } |
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| 106 | /// \brief End point of the path. |
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| 107 | /// |
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| 108 | /// End point of the path. |
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| 109 | /// Returns INVALID if the path is empty. |
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[986] | 110 | GraphNode target() const { |
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| 111 | return empty() ? INVALID : gr->target(edges[length()-1]); |
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[819] | 112 | } |
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| 113 | |
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| 114 | /// \brief Initializes node or edge iterator to point to the first |
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| 115 | /// node or edge. |
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| 116 | /// |
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| 117 | /// \sa nth |
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| 118 | template<typename It> |
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| 119 | It& first(It &i) const { return i=It(*this); } |
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| 120 | |
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| 121 | /// \brief Initializes node iterator to point to the node of a given index. |
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| 122 | NodeIt& nth(NodeIt &i, int n) const { |
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| 123 | return i=NodeIt(*this, n); |
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| 124 | } |
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| 125 | |
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| 126 | /// \brief Initializes edge iterator to point to the edge of a given index. |
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| 127 | EdgeIt& nth(EdgeIt &i, int n) const { |
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| 128 | return i=EdgeIt(*this, n); |
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| 129 | } |
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| 130 | |
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[986] | 131 | /// \brief Returns node iterator pointing to the target node of the |
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[819] | 132 | /// given edge iterator. |
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[986] | 133 | NodeIt target(const EdgeIt& e) const { |
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[819] | 134 | return NodeIt(*this, e.idx+1); |
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| 135 | } |
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| 136 | |
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[986] | 137 | /// \brief Returns node iterator pointing to the source node of the |
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[819] | 138 | /// given edge iterator. |
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[986] | 139 | NodeIt source(const EdgeIt& e) const { |
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[819] | 140 | return NodeIt(*this, e.idx); |
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| 141 | } |
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| 142 | |
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| 143 | |
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| 144 | /* Iterator classes */ |
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| 145 | |
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| 146 | /** |
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| 147 | * \brief Iterator class to iterate on the edges of the paths |
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[837] | 148 | * |
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[819] | 149 | * This class is used to iterate on the edges of the paths |
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| 150 | * |
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| 151 | * Of course it converts to Graph::Edge |
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[837] | 152 | * |
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[819] | 153 | */ |
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| 154 | class EdgeIt { |
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| 155 | friend class DirPath; |
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| 156 | |
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| 157 | int idx; |
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| 158 | const DirPath *p; |
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| 159 | public: |
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| 160 | /// Default constructor |
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| 161 | EdgeIt() {} |
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| 162 | /// Invalid constructor |
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| 163 | EdgeIt(Invalid) : idx(-1), p(0) {} |
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| 164 | /// Constructor with starting point |
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| 165 | EdgeIt(const DirPath &_p, int _idx = 0) : |
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| 166 | idx(_idx), p(&_p) { validate(); } |
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| 167 | |
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| 168 | ///Validity check |
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| 169 | bool valid() const { return idx!=-1; } |
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| 170 | |
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| 171 | ///Conversion to Graph::Edge |
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| 172 | operator GraphEdge () const { |
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| 173 | return valid() ? p->edges[idx] : INVALID; |
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| 174 | } |
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| 175 | |
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| 176 | /// Next edge |
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| 177 | EdgeIt& operator++() { ++idx; validate(); return *this; } |
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| 178 | |
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| 179 | /// Comparison operator |
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| 180 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
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| 181 | /// Comparison operator |
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| 182 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
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| 183 | /// Comparison operator |
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| 184 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
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| 185 | |
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| 186 | private: |
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[1282] | 187 | void validate() { if(idx >= p->length() ) idx=-1; } |
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[819] | 188 | }; |
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| 189 | |
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| 190 | /** |
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| 191 | * \brief Iterator class to iterate on the nodes of the paths |
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[837] | 192 | * |
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[819] | 193 | * This class is used to iterate on the nodes of the paths |
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| 194 | * |
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| 195 | * Of course it converts to Graph::Node |
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[837] | 196 | * |
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[819] | 197 | */ |
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| 198 | class NodeIt { |
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| 199 | friend class DirPath; |
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| 200 | |
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| 201 | int idx; |
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| 202 | const DirPath *p; |
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| 203 | public: |
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| 204 | /// Default constructor |
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| 205 | NodeIt() {} |
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| 206 | /// Invalid constructor |
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| 207 | NodeIt(Invalid) : idx(-1), p(0) {} |
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| 208 | /// Constructor with starting point |
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| 209 | NodeIt(const DirPath &_p, int _idx = 0) : |
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| 210 | idx(_idx), p(&_p) { validate(); } |
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| 211 | |
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| 212 | ///Validity check |
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| 213 | bool valid() const { return idx!=-1; } |
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| 214 | |
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| 215 | ///Conversion to Graph::Node |
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[2045] | 216 | operator GraphNode () const { |
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[819] | 217 | if(idx >= p->length()) |
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[986] | 218 | return p->target(); |
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[819] | 219 | else if(idx >= 0) |
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[986] | 220 | return p->gr->source(p->edges[idx]); |
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[819] | 221 | else |
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| 222 | return INVALID; |
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| 223 | } |
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| 224 | /// Next node |
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| 225 | NodeIt& operator++() { ++idx; validate(); return *this; } |
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| 226 | |
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| 227 | /// Comparison operator |
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| 228 | bool operator==(const NodeIt& e) const { return idx==e.idx; } |
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| 229 | /// Comparison operator |
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| 230 | bool operator!=(const NodeIt& e) const { return idx!=e.idx; } |
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| 231 | /// Comparison operator |
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| 232 | bool operator<(const NodeIt& e) const { return idx<e.idx; } |
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| 233 | |
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| 234 | private: |
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[1282] | 235 | void validate() { if(idx > p->length() ) idx=-1; } |
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[819] | 236 | }; |
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| 237 | |
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[837] | 238 | friend class Builder; |
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[819] | 239 | |
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| 240 | /** |
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| 241 | * \brief Class to build paths |
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[837] | 242 | * |
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[819] | 243 | * This class is used to fill a path with edges. |
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| 244 | * |
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| 245 | * You can push new edges to the front and to the back of the path in |
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| 246 | * arbitrary order then you should commit these changes to the graph. |
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| 247 | * |
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| 248 | * Fundamentally, for most "Paths" (classes fulfilling the |
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| 249 | * PathConcept) while the builder is active (after the first modifying |
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| 250 | * operation and until the commit()) the original Path is in a |
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| 251 | * "transitional" state (operations on it have undefined result). But |
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| 252 | * in the case of DirPath the original path remains unchanged until the |
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| 253 | * commit. However we don't recomend that you use this feature. |
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| 254 | */ |
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| 255 | class Builder { |
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| 256 | DirPath &P; |
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| 257 | Container front, back; |
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| 258 | |
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| 259 | public: |
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[1228] | 260 | ///\param _p the path you want to fill in. |
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[819] | 261 | /// |
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[1228] | 262 | Builder(DirPath &_p) : P(_p) {} |
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[819] | 263 | |
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| 264 | /// Sets the starting node of the path. |
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[837] | 265 | |
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[819] | 266 | /// Sets the starting node of the path. Edge added to the path |
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| 267 | /// afterwards have to be incident to this node. |
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[900] | 268 | /// It should be called if and only if |
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| 269 | /// the path is empty and before any call to |
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[819] | 270 | /// \ref pushFront() or \ref pushBack() |
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| 271 | void setStartNode(const GraphNode &) {} |
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| 272 | |
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| 273 | ///Push a new edge to the front of the path |
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| 274 | |
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| 275 | ///Push a new edge to the front of the path. |
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| 276 | ///\sa setStartNode |
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| 277 | void pushFront(const GraphEdge& e) { |
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| 278 | front.push_back(e); |
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| 279 | } |
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| 280 | |
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| 281 | ///Push a new edge to the back of the path |
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| 282 | |
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| 283 | ///Push a new edge to the back of the path. |
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| 284 | ///\sa setStartNode |
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| 285 | void pushBack(const GraphEdge& e) { |
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| 286 | back.push_back(e); |
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| 287 | } |
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| 288 | |
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| 289 | ///Commit the changes to the path. |
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| 290 | void commit() { |
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[837] | 291 | if( !front.empty() || !back.empty() ) { |
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[819] | 292 | Container tmp; |
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| 293 | tmp.reserve(front.size()+back.size()+P.length()); |
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| 294 | tmp.insert(tmp.end(), front.rbegin(), front.rend()); |
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| 295 | tmp.insert(tmp.end(), P.edges.begin(), P.edges.end()); |
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| 296 | tmp.insert(tmp.end(), back.begin(), back.end()); |
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| 297 | P.edges.swap(tmp); |
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| 298 | front.clear(); |
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| 299 | back.clear(); |
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| 300 | } |
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| 301 | } |
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| 302 | |
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| 303 | ///Reserve storage for the builder in advance. |
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| 304 | |
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[837] | 305 | ///If you know a reasonable upper bound of the number of the edges |
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| 306 | ///to add to the front, using this function you can speed up the building. |
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[819] | 307 | |
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[837] | 308 | void reserveFront(size_t r) {front.reserve(r);} |
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| 309 | |
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| 310 | ///Reserve storage for the builder in advance. |
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| 311 | |
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| 312 | ///If you know a reasonable upper bound of the number of the edges |
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| 313 | ///to add to the back, using this function you can speed up the building. |
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| 314 | |
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| 315 | void reserveBack(size_t r) {back.reserve(r);} |
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[831] | 316 | |
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[819] | 317 | private: |
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| 318 | bool empty() { |
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| 319 | return front.empty() && back.empty() && P.empty(); |
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| 320 | } |
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| 321 | |
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[986] | 322 | GraphNode source() const { |
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[819] | 323 | if( ! front.empty() ) |
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[986] | 324 | return P.gr->source(front[front.size()-1]); |
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[819] | 325 | else if( ! P.empty() ) |
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[986] | 326 | return P.gr->source(P.edges[0]); |
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[819] | 327 | else if( ! back.empty() ) |
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[986] | 328 | return P.gr->source(back[0]); |
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[819] | 329 | else |
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| 330 | return INVALID; |
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| 331 | } |
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[986] | 332 | GraphNode target() const { |
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[819] | 333 | if( ! back.empty() ) |
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[986] | 334 | return P.gr->target(back[back.size()-1]); |
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[819] | 335 | else if( ! P.empty() ) |
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[986] | 336 | return P.gr->target(P.edges[P.length()-1]); |
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[819] | 337 | else if( ! front.empty() ) |
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[986] | 338 | return P.gr->target(front[0]); |
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[819] | 339 | else |
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| 340 | return INVALID; |
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| 341 | } |
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| 342 | |
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| 343 | }; |
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| 344 | |
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| 345 | }; |
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| 346 | |
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| 347 | |
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| 348 | |
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| 349 | |
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| 350 | |
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| 351 | |
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| 352 | |
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| 353 | |
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| 354 | |
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| 355 | |
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| 356 | /**********************************************************************/ |
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| 357 | |
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| 358 | |
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| 359 | //! \brief A structure for representing undirected path in a graph. |
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| 360 | //! |
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| 361 | //! A structure for representing undirected path in a graph. Ie. this is |
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| 362 | //! a path in a \e directed graph but the edges should not be directed |
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| 363 | //! forward. |
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| 364 | //! |
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| 365 | //! \param Graph The graph type in which the path is. |
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| 366 | //! \param DM DebugMode, defaults to DefaultDebugMode. |
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[837] | 367 | //! |
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[819] | 368 | //! In a sense, the path can be treated as a graph, for is has \c NodeIt |
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| 369 | //! and \c EdgeIt with the same usage. These types converts to the \c Node |
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| 370 | //! and \c Edge of the original graph. |
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| 371 | //! |
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| 372 | //! \todo Thoroughfully check all the range and consistency tests. |
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[1730] | 373 | /// \todo May we need just path for undirected graph instead of this. |
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[831] | 374 | template<typename Graph> |
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[1909] | 375 | class UPath { |
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[819] | 376 | public: |
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| 377 | /// Edge type of the underlying graph. |
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| 378 | typedef typename Graph::Edge GraphEdge; |
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| 379 | /// Node type of the underlying graph. |
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| 380 | typedef typename Graph::Node GraphNode; |
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| 381 | class NodeIt; |
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| 382 | class EdgeIt; |
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| 383 | |
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| 384 | protected: |
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| 385 | const Graph *gr; |
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| 386 | typedef std::vector<GraphEdge> Container; |
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| 387 | Container edges; |
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| 388 | |
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| 389 | public: |
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| 390 | |
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| 391 | /// \param _G The graph in which the path is. |
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| 392 | /// |
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[1909] | 393 | UPath(const Graph &_G) : gr(&_G) {} |
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[819] | 394 | |
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| 395 | /// \brief Subpath constructor. |
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| 396 | /// |
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| 397 | /// Subpath defined by two nodes. |
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| 398 | /// \warning It is an error if the two edges are not in order! |
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[1909] | 399 | UPath(const UPath &P, const NodeIt &a, const NodeIt &b) { |
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[819] | 400 | gr = P.gr; |
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| 401 | edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx); |
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| 402 | } |
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| 403 | |
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| 404 | /// \brief Subpath constructor. |
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| 405 | /// |
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| 406 | /// Subpath defined by two edges. Contains edges in [a,b) |
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| 407 | /// \warning It is an error if the two edges are not in order! |
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[1909] | 408 | UPath(const UPath &P, const EdgeIt &a, const EdgeIt &b) { |
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[819] | 409 | gr = P.gr; |
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| 410 | edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx); |
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| 411 | } |
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| 412 | |
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| 413 | /// Length of the path. |
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| 414 | size_t length() const { return edges.size(); } |
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| 415 | /// Returns whether the path is empty. |
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| 416 | bool empty() const { return edges.empty(); } |
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| 417 | |
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| 418 | /// Resets the path to an empty path. |
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| 419 | void clear() { edges.clear(); } |
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| 420 | |
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| 421 | /// \brief Starting point of the path. |
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| 422 | /// |
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| 423 | /// Starting point of the path. |
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| 424 | /// Returns INVALID if the path is empty. |
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[986] | 425 | GraphNode source() const { |
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| 426 | return empty() ? INVALID : gr->source(edges[0]); |
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[819] | 427 | } |
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| 428 | /// \brief End point of the path. |
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| 429 | /// |
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| 430 | /// End point of the path. |
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| 431 | /// Returns INVALID if the path is empty. |
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[986] | 432 | GraphNode target() const { |
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| 433 | return empty() ? INVALID : gr->target(edges[length()-1]); |
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[819] | 434 | } |
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| 435 | |
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| 436 | /// \brief Initializes node or edge iterator to point to the first |
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| 437 | /// node or edge. |
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| 438 | /// |
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| 439 | /// \sa nth |
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| 440 | template<typename It> |
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| 441 | It& first(It &i) const { return i=It(*this); } |
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| 442 | |
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| 443 | /// \brief Initializes node iterator to point to the node of a given index. |
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| 444 | NodeIt& nth(NodeIt &i, int n) const { |
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| 445 | return i=NodeIt(*this, n); |
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| 446 | } |
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| 447 | |
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| 448 | /// \brief Initializes edge iterator to point to the edge of a given index. |
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| 449 | EdgeIt& nth(EdgeIt &i, int n) const { |
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| 450 | return i=EdgeIt(*this, n); |
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| 451 | } |
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| 452 | |
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| 453 | /// Checks validity of a node or edge iterator. |
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| 454 | template<typename It> |
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| 455 | static |
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| 456 | bool valid(const It &i) { return i.valid(); } |
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| 457 | |
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| 458 | /// Steps the given node or edge iterator. |
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| 459 | template<typename It> |
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| 460 | static |
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| 461 | It& next(It &e) { |
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| 462 | return ++e; |
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| 463 | } |
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| 464 | |
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[986] | 465 | /// \brief Returns node iterator pointing to the target node of the |
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[819] | 466 | /// given edge iterator. |
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[986] | 467 | NodeIt target(const EdgeIt& e) const { |
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[819] | 468 | return NodeIt(*this, e.idx+1); |
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| 469 | } |
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| 470 | |
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[986] | 471 | /// \brief Returns node iterator pointing to the source node of the |
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[819] | 472 | /// given edge iterator. |
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[986] | 473 | NodeIt source(const EdgeIt& e) const { |
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[819] | 474 | return NodeIt(*this, e.idx); |
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| 475 | } |
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| 476 | |
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| 477 | |
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| 478 | |
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| 479 | /** |
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| 480 | * \brief Iterator class to iterate on the edges of the paths |
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[837] | 481 | * |
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[819] | 482 | * This class is used to iterate on the edges of the paths |
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| 483 | * |
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| 484 | * Of course it converts to Graph::Edge |
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[837] | 485 | * |
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[819] | 486 | * \todo Its interface differs from the standard edge iterator. |
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| 487 | * Yes, it shouldn't. |
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| 488 | */ |
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| 489 | class EdgeIt { |
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[1909] | 490 | friend class UPath; |
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[819] | 491 | |
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| 492 | int idx; |
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[1909] | 493 | const UPath *p; |
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[819] | 494 | public: |
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| 495 | /// Default constructor |
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| 496 | EdgeIt() {} |
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| 497 | /// Invalid constructor |
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| 498 | EdgeIt(Invalid) : idx(-1), p(0) {} |
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| 499 | /// Constructor with starting point |
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[1909] | 500 | EdgeIt(const UPath &_p, int _idx = 0) : |
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[819] | 501 | idx(_idx), p(&_p) { validate(); } |
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| 502 | |
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| 503 | ///Validity check |
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| 504 | bool valid() const { return idx!=-1; } |
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| 505 | |
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| 506 | ///Conversion to Graph::Edge |
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| 507 | operator GraphEdge () const { |
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| 508 | return valid() ? p->edges[idx] : INVALID; |
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| 509 | } |
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| 510 | /// Next edge |
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| 511 | EdgeIt& operator++() { ++idx; validate(); return *this; } |
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| 512 | |
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| 513 | /// Comparison operator |
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| 514 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
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| 515 | /// Comparison operator |
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| 516 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
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| 517 | /// Comparison operator |
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| 518 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
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| 519 | |
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| 520 | private: |
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| 521 | // FIXME: comparison between signed and unsigned... |
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| 522 | // Jo ez igy? Vagy esetleg legyen a length() int? |
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| 523 | void validate() { if( size_t(idx) >= p->length() ) idx=-1; } |
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| 524 | }; |
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| 525 | |
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| 526 | /** |
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| 527 | * \brief Iterator class to iterate on the nodes of the paths |
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[837] | 528 | * |
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[819] | 529 | * This class is used to iterate on the nodes of the paths |
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| 530 | * |
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| 531 | * Of course it converts to Graph::Node |
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[837] | 532 | * |
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[819] | 533 | * \todo Its interface differs from the standard node iterator. |
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| 534 | * Yes, it shouldn't. |
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| 535 | */ |
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| 536 | class NodeIt { |
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[1909] | 537 | friend class UPath; |
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[819] | 538 | |
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| 539 | int idx; |
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[1909] | 540 | const UPath *p; |
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[819] | 541 | public: |
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| 542 | /// Default constructor |
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| 543 | NodeIt() {} |
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| 544 | /// Invalid constructor |
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| 545 | NodeIt(Invalid) : idx(-1), p(0) {} |
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| 546 | /// Constructor with starting point |
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[1909] | 547 | NodeIt(const UPath &_p, int _idx = 0) : |
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[819] | 548 | idx(_idx), p(&_p) { validate(); } |
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| 549 | |
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| 550 | ///Validity check |
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| 551 | bool valid() const { return idx!=-1; } |
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| 552 | |
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| 553 | ///Conversion to Graph::Node |
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| 554 | operator const GraphNode& () const { |
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| 555 | if(idx >= p->length()) |
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[986] | 556 | return p->target(); |
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[819] | 557 | else if(idx >= 0) |
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[986] | 558 | return p->gr->source(p->edges[idx]); |
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[819] | 559 | else |
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| 560 | return INVALID; |
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| 561 | } |
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| 562 | /// Next node |
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| 563 | NodeIt& operator++() { ++idx; validate(); return *this; } |
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| 564 | |
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| 565 | /// Comparison operator |
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| 566 | bool operator==(const NodeIt& e) const { return idx==e.idx; } |
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| 567 | /// Comparison operator |
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| 568 | bool operator!=(const NodeIt& e) const { return idx!=e.idx; } |
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| 569 | /// Comparison operator |
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| 570 | bool operator<(const NodeIt& e) const { return idx<e.idx; } |
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| 571 | |
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| 572 | private: |
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| 573 | void validate() { if( size_t(idx) > p->length() ) idx=-1; } |
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| 574 | }; |
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| 575 | |
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[837] | 576 | friend class Builder; |
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[819] | 577 | |
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| 578 | /** |
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| 579 | * \brief Class to build paths |
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[837] | 580 | * |
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[819] | 581 | * This class is used to fill a path with edges. |
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| 582 | * |
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| 583 | * You can push new edges to the front and to the back of the path in |
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| 584 | * arbitrary order then you should commit these changes to the graph. |
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| 585 | * |
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| 586 | * Fundamentally, for most "Paths" (classes fulfilling the |
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| 587 | * PathConcept) while the builder is active (after the first modifying |
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| 588 | * operation and until the commit()) the original Path is in a |
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| 589 | * "transitional" state (operations ot it have undefined result). But |
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[1909] | 590 | * in the case of UPath the original path is unchanged until the |
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[819] | 591 | * commit. However we don't recomend that you use this feature. |
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| 592 | */ |
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| 593 | class Builder { |
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[1909] | 594 | UPath &P; |
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[819] | 595 | Container front, back; |
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| 596 | |
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| 597 | public: |
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[1228] | 598 | ///\param _p the path you want to fill in. |
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[819] | 599 | /// |
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[1909] | 600 | Builder(UPath &_p) : P(_p) {} |
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[819] | 601 | |
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| 602 | /// Sets the starting node of the path. |
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[837] | 603 | |
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[819] | 604 | /// Sets the starting node of the path. Edge added to the path |
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| 605 | /// afterwards have to be incident to this node. |
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[900] | 606 | /// It should be called if and only if |
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| 607 | /// the path is empty and before any call to |
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[819] | 608 | /// \ref pushFront() or \ref pushBack() |
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| 609 | void setStartNode(const GraphNode &) {} |
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| 610 | |
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| 611 | ///Push a new edge to the front of the path |
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| 612 | |
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| 613 | ///Push a new edge to the front of the path. |
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| 614 | ///\sa setStartNode |
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| 615 | void pushFront(const GraphEdge& e) { |
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| 616 | front.push_back(e); |
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| 617 | } |
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| 618 | |
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| 619 | ///Push a new edge to the back of the path |
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| 620 | |
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| 621 | ///Push a new edge to the back of the path. |
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| 622 | ///\sa setStartNode |
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| 623 | void pushBack(const GraphEdge& e) { |
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| 624 | back.push_back(e); |
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| 625 | } |
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| 626 | |
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| 627 | ///Commit the changes to the path. |
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| 628 | void commit() { |
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| 629 | if( !(front.empty() && back.empty()) ) { |
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| 630 | Container tmp; |
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| 631 | tmp.reserve(front.size()+back.size()+P.length()); |
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| 632 | tmp.insert(tmp.end(), front.rbegin(), front.rend()); |
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| 633 | tmp.insert(tmp.end(), P.edges.begin(), P.edges.end()); |
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| 634 | tmp.insert(tmp.end(), back.begin(), back.end()); |
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| 635 | P.edges.swap(tmp); |
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| 636 | front.clear(); |
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| 637 | back.clear(); |
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| 638 | } |
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| 639 | } |
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| 640 | |
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| 641 | |
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| 642 | ///Reserve storage for the builder in advance. |
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| 643 | |
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[837] | 644 | ///If you know a reasonable upper bound of the number of the edges |
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| 645 | ///to add to the front, using this function you can speed up the building. |
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[819] | 646 | |
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[837] | 647 | void reserveFront(size_t r) {front.reserve(r);} |
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| 648 | |
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| 649 | ///Reserve storage for the builder in advance. |
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| 650 | |
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| 651 | ///If you know a reasonable upper bound of the number of the edges |
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| 652 | ///to add to the back, using this function you can speed up the building. |
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| 653 | |
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| 654 | void reserveBack(size_t r) {back.reserve(r);} |
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[831] | 655 | |
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[819] | 656 | private: |
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| 657 | bool empty() { |
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| 658 | return front.empty() && back.empty() && P.empty(); |
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| 659 | } |
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| 660 | |
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[986] | 661 | GraphNode source() const { |
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[819] | 662 | if( ! front.empty() ) |
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[986] | 663 | return P.gr->source(front[front.size()-1]); |
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[819] | 664 | else if( ! P.empty() ) |
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[986] | 665 | return P.gr->source(P.edges[0]); |
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[819] | 666 | else if( ! back.empty() ) |
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[986] | 667 | return P.gr->source(back[0]); |
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[819] | 668 | else |
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| 669 | return INVALID; |
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| 670 | } |
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[986] | 671 | GraphNode target() const { |
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[819] | 672 | if( ! back.empty() ) |
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[986] | 673 | return P.gr->target(back[back.size()-1]); |
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[819] | 674 | else if( ! P.empty() ) |
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[986] | 675 | return P.gr->target(P.edges[P.length()-1]); |
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[819] | 676 | else if( ! front.empty() ) |
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[986] | 677 | return P.gr->target(front[0]); |
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[819] | 678 | else |
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| 679 | return INVALID; |
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| 680 | } |
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| 681 | |
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| 682 | }; |
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| 683 | |
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| 684 | }; |
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| 685 | |
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| 686 | |
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| 687 | ///@} |
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| 688 | |
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[921] | 689 | } // namespace lemon |
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[819] | 690 | |
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[921] | 691 | #endif // LEMON_PATH_H |
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