[1623] | 1 | /* -*- C++ -*- |
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| 2 | * lemon/grid_graph.h - Part of LEMON, a generic C++ optimization library |
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| 3 | * |
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| 4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 5 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 6 | * |
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| 7 | * Permission to use, modify and distribute this software is granted |
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| 8 | * provided that this copyright notice appears in all copies. For |
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| 9 | * precise terms see the accompanying LICENSE file. |
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| 10 | * |
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| 11 | * This software is provided "AS IS" with no warranty of any kind, |
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| 12 | * express or implied, and with no claim as to its suitability for any |
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| 13 | * purpose. |
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| 14 | * |
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| 15 | */ |
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| 16 | |
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| 17 | #ifndef GRID_GRAPH_H |
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| 18 | #define GRID_GRAPH_H |
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| 19 | |
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| 20 | #include <iostream> |
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| 21 | #include <lemon/invalid.h> |
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| 22 | #include <lemon/utility.h> |
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| 23 | |
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| 24 | #include <lemon/bits/iterable_graph_extender.h> |
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| 25 | #include <lemon/bits/alteration_notifier.h> |
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| 26 | #include <lemon/bits/default_map.h> |
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| 27 | |
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| 28 | #include <lemon/bits/undir_graph_extender.h> |
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| 29 | |
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| 30 | namespace lemon { |
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| 31 | |
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| 32 | class GridGraphBase { |
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| 33 | |
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| 34 | public: |
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| 35 | |
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| 36 | typedef GridGraphBase Graph; |
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| 37 | |
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| 38 | class Node; |
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| 39 | class Edge; |
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| 40 | |
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| 41 | public: |
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| 42 | |
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| 43 | GridGraphBase() {} |
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| 44 | |
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| 45 | protected: |
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| 46 | |
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| 47 | /// \brief Creates a grid graph with the given size. |
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| 48 | /// |
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| 49 | /// Creates a grid graph with the given size. |
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| 50 | void construct(int height, int width) { |
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| 51 | _height = height; _width = width; |
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| 52 | _nodeNum = height * width; _edgeNum = 2 * _nodeNum - width - height; |
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| 53 | _edgeLimit = _nodeNum - width; |
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| 54 | } |
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| 55 | |
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| 56 | public: |
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| 57 | |
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| 58 | /// \brief The node on the given position. |
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| 59 | /// |
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| 60 | /// Gives back the node on the given position. |
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| 61 | Node operator()(int i, int j) const { |
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| 62 | return Node(i * _width + j); |
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| 63 | } |
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| 64 | |
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| 65 | /// \brief Gives back the row index of the node. |
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| 66 | /// |
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| 67 | /// Gives back the row index of the node. |
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| 68 | int row(Node n) const { |
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| 69 | return n.id / _width; |
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| 70 | } |
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| 71 | |
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| 72 | /// \brief Gives back the coloumn index of the node. |
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| 73 | /// |
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| 74 | /// Gives back the coloumn index of the node. |
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| 75 | int col(Node node) const { |
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| 76 | return n.id % _width; |
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| 77 | } |
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| 78 | |
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| 79 | /// \brief Gives back the width of the graph. |
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| 80 | /// |
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| 81 | /// Gives back the width of the graph. |
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| 82 | int width() const { |
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| 83 | return _width; |
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| 84 | } |
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| 85 | |
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| 86 | /// \brief Gives back the height of the graph. |
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| 87 | /// |
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| 88 | /// Gives back the height of the graph. |
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| 89 | int height() const { |
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| 90 | return _height; |
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| 91 | } |
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| 92 | |
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| 93 | typedef True NodeNumTag; |
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| 94 | typedef True EdgeNumTag; |
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| 95 | |
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| 96 | ///Number of nodes. |
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| 97 | int nodeNum() const { return _nodeNum; } |
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| 98 | ///Number of edges. |
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| 99 | int edgeNum() const { return _edgeNum; } |
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| 100 | |
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| 101 | /// Maximum node ID. |
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| 102 | |
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| 103 | /// Maximum node ID. |
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| 104 | ///\sa id(Node) |
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| 105 | int maxId(Node = INVALID) const { return nodeNum() - 1; } |
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| 106 | /// Maximum edge ID. |
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| 107 | |
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| 108 | /// Maximum edge ID. |
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| 109 | ///\sa id(Edge) |
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| 110 | int maxId(Edge = INVALID) const { return edgeNum() - 1; } |
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| 111 | |
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| 112 | /// \brief Gives back the source node of an edge. |
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| 113 | /// |
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| 114 | /// Gives back the source node of an edge. |
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| 115 | Node source(Edge e) const { |
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| 116 | if (e.id < _edgeLimit) { |
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| 117 | return e.id; |
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| 118 | } else { |
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| 119 | return (e.id - _edgeLimit) % (_width - 1) + |
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| 120 | (e.id - _edgeLimit) / (_width - 1) * _width; |
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| 121 | } |
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| 122 | } |
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| 123 | |
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| 124 | /// \brief Gives back the target node of an edge. |
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| 125 | /// |
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| 126 | /// Gives back the target node of an edge. |
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| 127 | Node target(Edge e) const { |
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| 128 | if (e.id < _edgeLimit) { |
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| 129 | return e.id + _width; |
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| 130 | } else { |
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| 131 | return (e.id - _edgeLimit) % (_width - 1) + |
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| 132 | (e.id - _edgeLimit) / (_width - 1) * _width + 1; |
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| 133 | } |
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| 134 | } |
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| 135 | |
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| 136 | /// Node ID. |
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| 137 | |
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| 138 | /// The ID of a valid Node is a nonnegative integer not greater than |
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| 139 | /// \ref maxNodeId(). The range of the ID's is not surely continuous |
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| 140 | /// and the greatest node ID can be actually less then \ref maxNodeId(). |
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| 141 | /// |
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| 142 | /// The ID of the \ref INVALID node is -1. |
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| 143 | ///\return The ID of the node \c v. |
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| 144 | |
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| 145 | static int id(Node v) { return v.id; } |
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| 146 | /// Edge ID. |
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| 147 | |
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| 148 | /// The ID of a valid Edge is a nonnegative integer not greater than |
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| 149 | /// \ref maxEdgeId(). The range of the ID's is not surely continuous |
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| 150 | /// and the greatest edge ID can be actually less then \ref maxEdgeId(). |
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| 151 | /// |
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| 152 | /// The ID of the \ref INVALID edge is -1. |
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| 153 | ///\return The ID of the edge \c e. |
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| 154 | static int id(Edge e) { return e.id; } |
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| 155 | |
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| 156 | static Node fromId(int id, Node) { return Node(id);} |
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| 157 | |
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| 158 | static Edge fromId(int id, Edge) { return Edge(id);} |
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| 159 | |
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| 160 | typedef True FindEdgeTag; |
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| 161 | |
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| 162 | /// Finds an edge between two nodes. |
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| 163 | |
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| 164 | /// Finds an edge from node \c u to node \c v. |
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| 165 | /// |
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| 166 | /// If \c prev is \ref INVALID (this is the default value), then |
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| 167 | /// It finds the first edge from \c u to \c v. Otherwise it looks for |
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| 168 | /// the next edge from \c u to \c v after \c prev. |
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| 169 | /// \return The found edge or INVALID if there is no such an edge. |
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| 170 | Edge findEdge(Node u, Node v, Edge prev = INVALID) { |
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| 171 | if (prev != INVALID) return INVALID; |
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| 172 | if (v.id - u.id == _width) return Edge(u.id); |
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| 173 | if (v.id - u.id == 1 && u.id % _width < _width - 1) { |
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| 174 | return Edge(u.id / _width * (_width - 1) + |
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| 175 | u.id % _width + _edgeLimit); |
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| 176 | } |
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| 177 | return INVALID; |
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| 178 | } |
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| 179 | |
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| 180 | |
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| 181 | class Node { |
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| 182 | friend class GridGraphBase; |
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| 183 | |
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| 184 | protected: |
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| 185 | int id; |
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| 186 | Node(int _id) { id = _id;} |
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| 187 | public: |
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| 188 | Node() {} |
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| 189 | Node (Invalid) { id = -1; } |
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| 190 | bool operator==(const Node node) const {return id == node.id;} |
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| 191 | bool operator!=(const Node node) const {return id != node.id;} |
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| 192 | bool operator<(const Node node) const {return id < node.id;} |
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| 193 | }; |
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| 194 | |
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| 195 | |
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| 196 | |
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| 197 | class Edge { |
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| 198 | friend class GridGraphBase; |
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| 199 | |
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| 200 | protected: |
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| 201 | int id; |
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| 202 | |
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| 203 | Edge(int _id) : id(_id) {} |
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| 204 | |
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| 205 | public: |
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| 206 | Edge() { } |
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| 207 | Edge (Invalid) { id = -1; } |
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| 208 | bool operator==(const Edge edge) const {return id == edge.id;} |
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| 209 | bool operator!=(const Edge edge) const {return id != edge.id;} |
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| 210 | bool operator<(const Edge edge) const {return id < edge.id;} |
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| 211 | }; |
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| 212 | |
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| 213 | void first(Node& node) const { |
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| 214 | node.id = nodeNum() - 1; |
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| 215 | } |
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| 216 | |
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| 217 | static void next(Node& node) { |
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| 218 | --node.id; |
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| 219 | } |
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| 220 | |
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| 221 | void first(Edge& edge) const { |
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| 222 | edge.id = edgeNum() - 1; |
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| 223 | } |
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| 224 | |
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| 225 | static void next(Edge& edge) { |
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| 226 | --edge.id; |
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| 227 | } |
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| 228 | |
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| 229 | void firstOut(Edge& edge, const Node& node) const { |
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| 230 | if (node.id < _nodeNum - _width) { |
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| 231 | edge.id = node.id; |
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| 232 | } else if (node.id % _width < _width - 1) { |
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| 233 | edge.id = _edgeLimit + node.id % _width + |
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| 234 | (node.id / _width) * (_width - 1); |
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| 235 | } else { |
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| 236 | edge.id = -1; |
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| 237 | } |
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| 238 | } |
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| 239 | |
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| 240 | void nextOut(Edge& edge) const { |
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| 241 | if (edge.id >= _edgeLimit) { |
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| 242 | edge.id = -1; |
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| 243 | } else if (edge.id % _width < _width - 1) { |
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| 244 | edge.id = _edgeLimit + edge.id % _width + |
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| 245 | (edge.id / _width) * (_width - 1); |
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| 246 | } else { |
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| 247 | edge.id = -1; |
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| 248 | } |
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| 249 | } |
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| 250 | |
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| 251 | void firstIn(Edge& edge, const Node& node) const { |
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| 252 | if (node.id >= _width) { |
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| 253 | edge.id = node.id - _width; |
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| 254 | } else if (node.id % _width > 0) { |
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| 255 | edge.id = _edgeLimit + node.id % _width + |
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| 256 | (node.id / _width) * (_width - 1) - 1; |
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| 257 | } else { |
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| 258 | edge.id = -1; |
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| 259 | } |
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| 260 | } |
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| 261 | |
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| 262 | void nextIn(Edge& edge) const { |
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| 263 | if (edge.id >= _edgeLimit) { |
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| 264 | edge.id = -1; |
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| 265 | } else if (edge.id % _width > 0) { |
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| 266 | edge.id = _edgeLimit + edge.id % _width + |
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| 267 | (edge.id / _width + 1) * (_width - 1) - 1; |
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| 268 | } else { |
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| 269 | edge.id = -1; |
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| 270 | } |
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| 271 | } |
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| 272 | |
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| 273 | private: |
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| 274 | int _width, _height; |
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| 275 | int _nodeNum, _edgeNum; |
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| 276 | int _edgeLimit; |
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| 277 | }; |
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| 278 | |
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| 279 | |
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| 280 | typedef UndirGraphExtender<GridGraphBase> |
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| 281 | UndirGridGraphBase; |
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| 282 | typedef AlterableUndirGraphExtender<UndirGridGraphBase> |
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| 283 | AlterableGridGraphBase; |
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| 284 | typedef IterableUndirGraphExtender<AlterableGridGraphBase> |
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| 285 | IterableGridGraphBase; |
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| 286 | typedef MappableUndirGraphExtender<IterableGridGraphBase> |
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| 287 | MappableGridGraphBase; |
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| 288 | |
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| 289 | /// \ingroup graphs |
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| 290 | /// |
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| 291 | /// \brief Grid graph class |
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| 292 | /// |
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| 293 | /// This class implements a special graph type. The nodes of the |
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| 294 | /// graph can be indiced by two integer \c (i,j) value where \c i |
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| 295 | /// is in the \c [0,height) range and j is in the [0, width) range. |
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| 296 | /// Two nodes are connected in the graph if the indices differ only |
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| 297 | /// on one position and only one is the difference. |
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| 298 | /// |
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| 299 | /// The graph can be indiced in the following way: |
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| 300 | /// \code |
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| 301 | /// GridGraph graph(h, w); |
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| 302 | /// GridGraph::NodeMap<int> val(graph); |
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| 303 | /// for (int i = 0; i < graph.height(); ++i) { |
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| 304 | /// for (int j = 0; j < graph.width(); ++j) { |
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| 305 | /// val[graph(i, j)] = i + j; |
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| 306 | /// } |
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| 307 | /// } |
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| 308 | /// \endcode |
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| 309 | /// |
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| 310 | /// The graph type is fully conform to the \ref concept::UndirGraph |
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| 311 | /// "Undirected Graph" concept. |
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| 312 | /// |
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| 313 | /// \author Balazs Dezso |
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| 314 | class GridGraph : public MappableGridGraphBase { |
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| 315 | public: |
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| 316 | |
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| 317 | GridGraph(int m, int n) { construct(m, n); } |
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| 318 | }; |
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| 319 | } |
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| 320 | #endif |
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