1 //=======================================================================
2 // Copyright 2001 Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee,
3 //
4 // Distributed under the Boost Software License, Version 1.0. (See
5 // accompanying file LICENSE_1_0.txt or copy at
6 // http://www.boost.org/LICENSE_1_0.txt)
7 //=======================================================================
8 #include <boost/graph/adjacency_list.hpp>
9 #include <boost/graph/kruskal_min_spanning_tree.hpp>
10 #include <iostream>
11 #include <fstream>
12
13 int
main()14 main()
15 {
16 using namespace boost;
17 typedef adjacency_list < vecS, vecS, undirectedS,
18 no_property, property < edge_weight_t, int > > Graph;
19 typedef graph_traits < Graph >::edge_descriptor Edge;
20 typedef graph_traits < Graph >::vertex_descriptor Vertex;
21 typedef std::pair<int, int> E;
22
23 const int num_nodes = 5;
24 E edge_array[] = { E(0, 2), E(1, 3), E(1, 4), E(2, 1), E(2, 3),
25 E(3, 4), E(4, 0), E(4, 1)
26 };
27 int weights[] = { 1, 1, 2, 7, 3, 1, 1, 1 };
28 std::size_t num_edges = sizeof(edge_array) / sizeof(E);
29 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
30 Graph g(num_nodes);
31 property_map<Graph, edge_weight_t>::type weightmap = get(edge_weight, g);
32 for (std::size_t j = 0; j < num_edges; ++j) {
33 Edge e; bool inserted;
34 boost::tie(e, inserted) = add_edge(edge_array[j].first, edge_array[j].second, g);
35 weightmap[e] = weights[j];
36 }
37 #else
38 Graph g(edge_array, edge_array + num_edges, weights, num_nodes);
39 #endif
40 property_map < Graph, edge_weight_t >::type weight = get(edge_weight, g);
41 std::vector < Edge > spanning_tree;
42
43 kruskal_minimum_spanning_tree(g, std::back_inserter(spanning_tree));
44
45 std::cout << "Print the edges in the MST:" << std::endl;
46 for (std::vector < Edge >::iterator ei = spanning_tree.begin();
47 ei != spanning_tree.end(); ++ei) {
48 std::cout << source(*ei, g) << " <--> " << target(*ei, g)
49 << " with weight of " << weight[*ei]
50 << std::endl;
51 }
52
53 std::ofstream fout("figs/kruskal-eg.dot");
54 fout << "graph A {\n"
55 << " rankdir=LR\n"
56 << " size=\"3,3\"\n"
57 << " ratio=\"filled\"\n"
58 << " edge[style=\"bold\"]\n" << " node[shape=\"circle\"]\n";
59 graph_traits<Graph>::edge_iterator eiter, eiter_end;
60 for (boost::tie(eiter, eiter_end) = edges(g); eiter != eiter_end; ++eiter) {
61 fout << source(*eiter, g) << " -- " << target(*eiter, g);
62 if (std::find(spanning_tree.begin(), spanning_tree.end(), *eiter)
63 != spanning_tree.end())
64 fout << "[color=\"black\", label=\"" << get(edge_weight, g, *eiter)
65 << "\"];\n";
66 else
67 fout << "[color=\"gray\", label=\"" << get(edge_weight, g, *eiter)
68 << "\"];\n";
69 }
70 fout << "}\n";
71 return EXIT_SUCCESS;
72 }
73