ceph/src/boost/libs/graph/example/topo_sort.cpp

   1 //=======================================================================
   2 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
   3 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
   4 //
   5 // Distributed under the Boost Software License, Version 1.0. (See
   6 // accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8 //=======================================================================
   9 #include <boost/config.hpp>
  10 #include <iostream>
  11 #include <list>
  12 #include <algorithm>
  13 #include <boost/graph/adjacency_list.hpp>
  14 #include <boost/graph/topological_sort.hpp>
  15 #include <iterator>
  16 #include <utility>
  17
  18 typedef std::pair< std::size_t, std::size_t > Pair;
  19
  20 /*
  21   Topological sort example
  22
  23   The topological sort algorithm creates a linear ordering
  24   of the vertices such that if edge (u,v) appears in the graph,
  25   then u comes before v in the ordering.
  26
  27   Sample output:
  28
  29   A topological ordering: 2 5 0 1 4 3
  30
  31 */
  32
  33 int main(int, char*[])
  34 {
  35     // begin
  36     using namespace boost;
  37
  38     /* Topological sort will need to color the graph.  Here we use an
  39        internal decorator, so we "property" the color to the graph.
  40        */
  41     typedef adjacency_list< vecS, vecS, directedS,
  42         property< vertex_color_t, default_color_type > >
  43         Graph;
  44
  45     typedef boost::graph_traits< Graph >::vertex_descriptor Vertex;
  46     Pair edges[6] = { Pair(0, 1), Pair(2, 4), Pair(2, 5), Pair(0, 3),
  47         Pair(1, 4), Pair(4, 3) };
  48 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
  49     // VC++ can't handle the iterator constructor
  50     Graph G(6);
  51     for (std::size_t j = 0; j < 6; ++j)
  52         add_edge(edges[j].first, edges[j].second, G);
  53 #else
  54     Graph G(edges, edges + 6, 6);
  55 #endif
  56
  57     boost::property_map< Graph, vertex_index_t >::type id
  58         = get(vertex_index, G);
  59
  60     typedef std::vector< Vertex > container;
  61     container c;
  62     topological_sort(G, std::back_inserter(c));
  63
  64     std::cout << "A topological ordering: ";
  65     for (container::reverse_iterator ii = c.rbegin(); ii != c.rend(); ++ii)
  66         std::cout << id[*ii] << " ";
  67     std::cout << std::endl;
  68
  69     return 0;
  70 }