1 | /* -*- C++ -*- |
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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) 2003-2006 |
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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 | ///\ingroup demos |
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20 | ///\file |
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21 | ///\brief Demonstrating the Dfs class with topological ordering |
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22 | /// |
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23 | ///\include topological_ordering.cc |
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24 | |
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25 | #include <iostream> |
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26 | #include <string> |
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27 | #include <list> |
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28 | #include <lemon/list_graph.h> |
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29 | #include <lemon/maps.h> |
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30 | #include <lemon/dfs.h> |
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31 | |
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32 | using namespace lemon; |
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33 | |
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34 | |
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35 | template< typename GR > |
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36 | class SerializingWriteMap |
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37 | { |
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38 | public: |
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39 | typedef typename GR::Node Key; |
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40 | typedef bool Value; |
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41 | typedef std::list<Key> OrderedList; |
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42 | |
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43 | OrderedList order; |
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44 | |
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45 | SerializingWriteMap( const GR& ) {} |
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46 | |
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47 | void set( const Key& k, const Value& v ) { |
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48 | if( v ) order.push_front(k); |
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49 | } |
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50 | |
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51 | Value operator[] ( const Key& ) { |
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52 | return false; |
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53 | } |
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54 | }; |
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55 | |
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56 | |
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57 | int main() |
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58 | { |
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59 | std::cout << "Topological Ordering demo" << std::endl; |
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60 | |
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61 | // Create and build the graph |
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62 | ListGraph gr; |
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63 | ListGraph::NodeMap<std::string> label(gr); |
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64 | typedef ListGraph::Node Node; |
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65 | |
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66 | // This DAG example for topological ordering is from the book New Algorithms |
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67 | // (Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein) |
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68 | { |
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69 | Node belt = gr.addNode(); |
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70 | Node trousers = gr.addNode(); |
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71 | Node necktie = gr.addNode(); |
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72 | Node coat = gr.addNode(); |
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73 | Node socks = gr.addNode(); |
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74 | Node shirt = gr.addNode(); |
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75 | Node shoe = gr.addNode(); |
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76 | Node watch = gr.addNode(); |
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77 | Node pants = gr.addNode(); |
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78 | |
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79 | label[belt] = "Belt"; |
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80 | label[trousers] = "Trousers"; |
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81 | label[necktie] = "Necktie"; |
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82 | label[coat] = "Coat"; |
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83 | label[socks] = "Socks"; |
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84 | label[shirt] = "Shirt"; |
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85 | label[shoe] = "Shoe"; |
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86 | label[watch] = "Watch"; |
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87 | label[pants] = "Pants"; |
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88 | |
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89 | // Here we use a directed edge to indicate precedenc. |
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90 | // The source must precede the target. |
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91 | gr.addEdge( socks, shoe ); |
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92 | gr.addEdge( pants, shoe ); |
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93 | gr.addEdge( pants, trousers ); |
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94 | gr.addEdge( trousers, shoe ); |
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95 | gr.addEdge( trousers, belt ); |
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96 | gr.addEdge( belt, coat ); |
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97 | gr.addEdge( shirt, belt ); |
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98 | gr.addEdge( shirt, necktie ); |
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99 | gr.addEdge( necktie, coat ); |
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100 | } |
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101 | |
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102 | // Calculate topological order |
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103 | Dfs<ListGraph, Dfs<ListGraph>::DefProcessedMapTraits<SerializingWriteMap<ListGraph> > > dfs(gr); |
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104 | SerializingWriteMap<ListGraph> list(gr); |
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105 | dfs.processedMap(list); |
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106 | dfs.run(); |
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107 | |
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108 | // Write out the result |
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109 | std::cout << "One possible order to dress up:"; |
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110 | for( SerializingWriteMap<ListGraph>::OrderedList::iterator it = list.order.begin(); it != list.order.end(); ++it ) |
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111 | std::cout << " " << label[*it]; |
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112 | std::cout << std::endl; |
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113 | |
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114 | return 0; |
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115 | } |
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