graph/examples/kevin_bacon.cpp

//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// This file is part of the Boost Graph Library
//
// You should have received a copy of the License Agreement for the
// Boost Graph Library along with the software; see the file LICENSE.
// If not, contact Office of Research, University of Notre Dame, Notre
// Dame, IN 46556.
//
// Permission to modify the code and to distribute modified code is
// granted, provided the text of this NOTICE is retained, a notice that
// the code was modified is included with the above COPYRIGHT NOTICE and
// with the COPYRIGHT NOTICE in the LICENSE file, and that the LICENSE
// file is distributed with the modified code.
//
// LICENSOR MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.
// By way of example, but not limitation, Licensor MAKES NO
// REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY
// PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE COMPONENTS
// OR DOCUMENTATION WILL NOT INFRINGE ANY PATENTS, COPYRIGHTS, TRADEMARKS
// OR OTHER RIGHTS.
//=======================================================================
#include <iostream>
#include <fstream>
#include <string>
#include <boost/pending/stringtok.hpp>
#include <boost/utility.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/visitors.hpp>
#include <boost/graph/dijkstra_shortest_paths.hpp>
#include <map>

int
main()
{
  using namespace boost;
  using namespace std;
  using boost::stringtok;
  using boost::tie;

  ifstream datafile("./kevin_bacon.dat");
  if (!datafile) {
    cerr << "No ./kevin_bacon.dat file" << endl;
    return -1;
  }

  typedef plugin<name_tag, string, 
    plugin<weight_tag, int> > EdgePlugin;
  typedef plugin<name_tag, string> VertexPlugin;
  typedef adjacency_list<vecS, vecS, undirectedS, 
    VertexPlugin, EdgePlugin> Graph;

  typedef Graph::vertex_descriptor Vertex;
  typedef Graph::edge_descriptor Edge;

  typedef map<string, Vertex> NameVertexMap;
  NameVertexMap actors;
  Graph g;

  vertex_property_accessor<Graph, name_tag>::type 
    actor_name = get_vertex_property_accessor(g, name_tag());
  edge_property_accessor<Graph, name_tag>::type 
    connecting_movie = get_edge_property_accessor(g, name_tag());
  edge_property_accessor<Graph, weight_tag>::type 
    weight = get_edge_property_accessor(g, weight_tag());
  
  string line;
  while (getline(datafile,line)) {

    list<string> line_toks;
    stringtok(line_toks, line, "|");

    NameVertexMap::iterator pos; 
    bool inserted;
    Vertex u, v;

    list<string>::iterator i = line_toks.begin();

    tie(pos, inserted) = actors.insert(make_pair(*i, Vertex()));
    if (inserted) {
      u = add_vertex(g);
      actor_name[u] = *i;
      pos->second = u;
    } else
      u = pos->second;
    ++i;

    string movie_name = *i++;
      
    tie(pos, inserted) = actors.insert(make_pair(*i, Vertex()));
    if (inserted) {
      v = add_vertex(g);
      actor_name[v] = *i;
      pos->second = v;
    } else
      v = pos->second;

    Edge e;
    tie(e, inserted) = add_edge(g, u, v);
    if (inserted) {
      connecting_movie[e] = movie_name;
      weight[e] = 1;
    }
  }

  {
    Graph::edge_iterator i, end;
    for (tie(i, end) = edges(g); i != end; ++i)
      cout << actor_name[source(*i, g)] << " was in "
	   << connecting_movie[*i] << " with "
	   << actor_name[target(*i, g)] << endl;
  }

  {
    // Use Dijkstra's shortest paths algorithm to calculate the Bacon
    // numbers of all the actors in our graph.

    std::vector<int> bacon_number( num_vertices(g) );
    std::vector<default_color_type> color( num_vertices(g) );
    std::vector<Vertex> predecessor( num_vertices(g) );

    Vertex src = actors["Kevin Bacon"];
    
    dijkstra_shortest_paths
      (g, src, bacon_number.begin(),
       get_edge_property_accessor(g, weight_tag()),
       color.begin(),
       get_vertex_property_accessor(g, id_tag()),
       make_ucs_visitor(record_predecessors(predecessor.begin(), 
					    on_edge_relaxed())));

    Graph::vertex_iterator i, end;
    for (tie(i,end) = vertices(g); i != end; ++i)
      cout << actor_name[*i] << "'s bacon number is " 
	   << bacon_number[*i] << endl;

    // use the predecessors to determine shortest paths to kevin...
  }
  
  return 0;
}