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3rdparty/boost_1_81_0/libs/graph/example/kevin-bacon.cpp 3.66 KB
977ed18d   Hu Chunming   提交三方库
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  //=======================================================================
  // Copyright 2001 Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee,
  //
  // Distributed under the Boost Software License, Version 1.0. (See
  // accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  //=======================================================================
  #include <boost/config.hpp>
  #include <iostream>
  #include <fstream>
  #include <string>
  #include <boost/tokenizer.hpp>
  #include <boost/tuple/tuple.hpp>
  #include <boost/graph/adjacency_list.hpp>
  #include <boost/graph/visitors.hpp>
  #include <boost/graph/breadth_first_search.hpp>
  #include <map>
  
  using namespace boost;
  
  template < typename DistanceMap >
  class bacon_number_recorder : public default_bfs_visitor
  {
  public:
      bacon_number_recorder(DistanceMap dist) : d(dist) {}
  
      template < typename Edge, typename Graph >
      void tree_edge(Edge e, const Graph& g) const
      {
          typename graph_traits< Graph >::vertex_descriptor u = source(e, g),
                                                            v = target(e, g);
          d[v] = d[u] + 1;
      }
  
  private:
      DistanceMap d;
  };
  
  // Convenience function
  template < typename DistanceMap >
  bacon_number_recorder< DistanceMap > record_bacon_number(DistanceMap d)
  {
      return bacon_number_recorder< DistanceMap >(d);
  }
  
  int main(int argc, const char** argv)
  {
      std::ifstream datafile(argc >= 2 ? argv[1] : "./kevin-bacon.dat");
      if (!datafile)
      {
          std::cerr << "No ./kevin-bacon.dat file" << std::endl;
          return EXIT_FAILURE;
      }
  
      typedef adjacency_list< vecS, vecS, undirectedS,
          property< vertex_name_t, std::string >,
          property< edge_name_t, std::string > >
          Graph;
      Graph g;
  
      typedef property_map< Graph, vertex_name_t >::type actor_name_map_t;
      actor_name_map_t actor_name = get(vertex_name, g);
      typedef property_map< Graph, edge_name_t >::type movie_name_map_t;
      movie_name_map_t connecting_movie = get(edge_name, g);
  
      typedef graph_traits< Graph >::vertex_descriptor Vertex;
      typedef std::map< std::string, Vertex > NameVertexMap;
      NameVertexMap actors;
  
      for (std::string line; std::getline(datafile, line);)
      {
          char_delimiters_separator< char > sep(false, "", ";");
          tokenizer<> line_toks(line, sep);
          tokenizer<>::iterator i = line_toks.begin();
          std::string actors_name = *i++;
          NameVertexMap::iterator pos;
          bool inserted;
          Vertex u, v;
          boost::tie(pos, inserted)
              = actors.insert(std::make_pair(actors_name, Vertex()));
          if (inserted)
          {
              u = add_vertex(g);
              actor_name[u] = actors_name;
              pos->second = u;
          }
          else
              u = pos->second;
  
          std::string movie_name = *i++;
  
          boost::tie(pos, inserted) = actors.insert(std::make_pair(*i, Vertex()));
          if (inserted)
          {
              v = add_vertex(g);
              actor_name[v] = *i;
              pos->second = v;
          }
          else
              v = pos->second;
  
          graph_traits< Graph >::edge_descriptor e;
          boost::tie(e, inserted) = add_edge(u, v, g);
          if (inserted)
              connecting_movie[e] = movie_name;
      }
  
      std::vector< int > bacon_number(num_vertices(g));
  
      Vertex src = actors["Kevin Bacon"];
      bacon_number[src] = 0;
  
      breadth_first_search(
          g, src, visitor(record_bacon_number(&bacon_number[0])));
  
      graph_traits< Graph >::vertex_iterator i, end;
      for (boost::tie(i, end) = vertices(g); i != end; ++i)
      {
          std::cout << actor_name[*i] << " has a Bacon number of "
                    << bacon_number[*i] << std::endl;
      }
  
      return 0;
  }