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3rdparty/boost_1_81_0/libs/graph/example/dfs-example.cpp 3.45 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/graph/adjacency_list.hpp>
  #include <boost/graph/depth_first_search.hpp>
  #include <boost/range/irange.hpp>
  #include <boost/pending/indirect_cmp.hpp>
  
  #include <iostream>
  
  using namespace boost;
  template < typename TimeMap >
  class dfs_time_visitor : public default_dfs_visitor
  {
      typedef typename property_traits< TimeMap >::value_type T;
  
  public:
      dfs_time_visitor(TimeMap dmap, TimeMap fmap, T& t)
      : m_dtimemap(dmap), m_ftimemap(fmap), m_time(t)
      {
      }
      template < typename Vertex, typename Graph >
      void discover_vertex(Vertex u, const Graph& g) const
      {
          put(m_dtimemap, u, m_time++);
      }
      template < typename Vertex, typename Graph >
      void finish_vertex(Vertex u, const Graph& g) const
      {
          put(m_ftimemap, u, m_time++);
      }
      TimeMap m_dtimemap;
      TimeMap m_ftimemap;
      T& m_time;
  };
  
  int main()
  {
      // Select the graph type we wish to use
      typedef adjacency_list< vecS, vecS, directedS > graph_t;
      typedef graph_traits< graph_t >::vertices_size_type size_type;
      // Set up the vertex names
      enum
      {
          u,
          v,
          w,
          x,
          y,
          z,
          N
      };
      char name[] = { 'u', 'v', 'w', 'x', 'y', 'z' };
      // Specify the edges in the graph
      typedef std::pair< int, int > E;
      E edge_array[] = { E(u, v), E(u, x), E(x, v), E(y, x), E(v, y), E(w, y),
          E(w, z), E(z, z) };
  #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
      graph_t g(N);
      for (std::size_t j = 0; j < sizeof(edge_array) / sizeof(E); ++j)
          add_edge(edge_array[j].first, edge_array[j].second, g);
  #else
      graph_t g(edge_array, edge_array + sizeof(edge_array) / sizeof(E), N);
  #endif
  
      // discover time and finish time properties
      std::vector< size_type > dtime(num_vertices(g));
      std::vector< size_type > ftime(num_vertices(g));
      typedef iterator_property_map< std::vector< size_type >::iterator,
          property_map< graph_t, vertex_index_t >::const_type >
          time_pm_type;
      time_pm_type dtime_pm(dtime.begin(), get(vertex_index, g));
      time_pm_type ftime_pm(ftime.begin(), get(vertex_index, g));
      size_type t = 0;
      dfs_time_visitor< time_pm_type > vis(dtime_pm, ftime_pm, t);
  
      depth_first_search(g, visitor(vis));
  
      // use std::sort to order the vertices by their discover time
      std::vector< size_type > discover_order(N);
      integer_range< size_type > r(0, N);
      std::copy(r.begin(), r.end(), discover_order.begin());
      std::sort(discover_order.begin(), discover_order.end(),
          indirect_cmp< time_pm_type, std::less< size_type > >(dtime_pm));
      std::cout << "order of discovery: ";
      int i;
      for (i = 0; i < N; ++i)
          std::cout << name[discover_order[i]] << " ";
  
      std::vector< size_type > finish_order(N);
      std::copy(r.begin(), r.end(), finish_order.begin());
      std::sort(finish_order.begin(), finish_order.end(),
          indirect_cmp< time_pm_type, std::less< size_type > >(ftime_pm));
      std::cout << std::endl << "order of finish: ";
      for (i = 0; i < N; ++i)
          std::cout << name[finish_order[i]] << " ";
      std::cout << std::endl;
  
      return EXIT_SUCCESS;
  }