1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library. |
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4 | * |
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5 | * Copyright (C) 2003-2009 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #ifndef LEMON_NAUTY_READER_H |
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20 | #define LEMON_NAUTY_READER_H |
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21 | |
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22 | #include <vector> |
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23 | #include <iostream> |
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24 | #include <string> |
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25 | |
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26 | /// \ingroup nauty_group |
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27 | /// \file |
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28 | /// \brief Nauty file reader. |
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29 | |
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30 | namespace lemon { |
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31 | |
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32 | /// \ingroup nauty_group |
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33 | /// |
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34 | /// \brief Nauty file reader |
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35 | /// |
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36 | /// The \e geng program is in the \e gtools suite of the nauty |
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37 | /// package. This tool can generate all non-isomorphic undirected |
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38 | /// graphs of several classes with given node number (e.g. |
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39 | /// general, connected, biconnected, triangle-free, 4-cycle-free, |
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40 | /// bipartite and graphs with given edge number and degree |
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41 | /// constraints). This function reads a \e nauty \e graph6 \e format |
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42 | /// line from the given stream and builds it in the given graph. |
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43 | /// |
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44 | /// The site of nauty package: http://cs.anu.edu.au/~bdm/nauty/ |
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45 | /// |
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46 | /// For example, the number of all non-isomorphic planar graphs |
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47 | /// can be computed with the following code. |
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48 | ///\code |
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49 | /// int num = 0; |
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50 | /// SmartGraph graph; |
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51 | /// while (readNautyGraph(graph, std::cin)) { |
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52 | /// PlanarityChecking<SmartGraph> pc(graph); |
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53 | /// if (pc.run()) ++num; |
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54 | /// } |
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55 | /// std::cout << "Number of planar graphs: " << num << std::endl; |
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56 | ///\endcode |
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57 | /// |
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58 | /// The nauty files are quite huge, therefore instead of the direct |
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59 | /// file generation pipelining is recommended. For example, |
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60 | ///\code |
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61 | /// ./geng -c 10 | ./num_of_planar_graphs |
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62 | ///\endcode |
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63 | template <typename Graph> |
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64 | std::istream& readNautyGraph(Graph& graph, std::istream& is = std::cin) { |
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65 | graph.clear(); |
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66 | |
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67 | std::string line; |
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68 | if (getline(is, line)) { |
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69 | int index = 0; |
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70 | |
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71 | int n; |
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72 | |
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73 | if (line[index] == '>') { |
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74 | index += 10; |
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75 | } |
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76 | |
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77 | char c = line[index++]; c -= 63; |
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78 | if (c != 63) { |
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79 | n = int(c); |
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80 | } else { |
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81 | c = line[index++]; c -= 63; |
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82 | n = (int(c) << 12); |
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83 | c = line[index++]; c -= 63; |
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84 | n |= (int(c) << 6); |
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85 | c = line[index++]; c -= 63; |
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86 | n |= int(c); |
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87 | } |
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88 | |
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89 | std::vector<typename Graph::Node> nodes; |
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90 | for (int i = 0; i < n; ++i) { |
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91 | nodes.push_back(graph.addNode()); |
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92 | } |
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93 | |
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94 | int bit = -1; |
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95 | for (int j = 0; j < n; ++j) { |
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96 | for (int i = 0; i < j; ++i) { |
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97 | if (bit == -1) { |
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98 | c = line[index++]; c -= 63; |
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99 | bit = 5; |
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100 | } |
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101 | bool b = (c & (1 << (bit--))) != 0; |
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102 | |
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103 | if (b) { |
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104 | graph.addEdge(nodes[i], nodes[j]); |
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105 | } |
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106 | } |
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107 | } |
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108 | } |
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109 | return is; |
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110 | } |
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111 | } |
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112 | |
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113 | #endif |
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