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 std::pair<int, int> E;
21
22 const int num_nodes = 5;
23 E edge_array[] = { E(0, 2), E(1, 3), E(1, 4), E(2, 1), E(2, 3),
24 E(3, 4), E(4, 0), E(4, 1)
25 };
26 int weights[] = { 1, 1, 2, 7, 3, 1, 1, 1 };
27 std::size_t num_edges = sizeof(edge_array) / sizeof(E);
28 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
29 Graph g(num_nodes);
30 property_map<Graph, edge_weight_t>::type weightmap = get(edge_weight, g);
31 for (std::size_t j = 0; j < num_edges; ++j) {
32 Edge e; bool inserted;
33 boost::tie(e, inserted) = add_edge(edge_array[j].first, edge_array[j].second, g);
34 weightmap[e] = weights[j];
35 }
36 #else
37 Graph g(edge_array, edge_array + num_edges, weights, num_nodes);
38 #endif
39 property_map < Graph, edge_weight_t >::type weight = get(edge_weight, g);
40 std::vector < Edge > spanning_tree;
41
42 kruskal_minimum_spanning_tree(g, std::back_inserter(spanning_tree));
43
44 std::cout << "Print the edges in the MST:" << std::endl;
45 for (std::vector < Edge >::iterator ei = spanning_tree.begin();
46 ei != spanning_tree.end(); ++ei) {
47 std::cout << source(*ei, g) << " <--> " << target(*ei, g)
48 << " with weight of " << weight[*ei]
49 << std::endl;
50 }
51
52 std::ofstream fout("figs/kruskal-eg.dot");
53 fout << "graph A {\n"
54 << " rankdir=LR\n"
55 << " size=\"3,3\"\n"
56 << " ratio=\"filled\"\n"
57 << " edge[style=\"bold\"]\n" << " node[shape=\"circle\"]\n";
58 graph_traits<Graph>::edge_iterator eiter, eiter_end;
59 for (boost::tie(eiter, eiter_end) = edges(g); eiter != eiter_end; ++eiter) {
60 fout << source(*eiter, g) << " -- " << target(*eiter, g);
61 if (std::find(spanning_tree.begin(), spanning_tree.end(), *eiter)
62 != spanning_tree.end())
63 fout << "[color=\"black\", label=\"" << get(edge_weight, g, *eiter)
64 << "\"];\n";
65 else
66 fout << "[color=\"gray\", label=\"" << get(edge_weight, g, *eiter)
67 << "\"];\n";
68 }
69 fout << "}\n";
70 return EXIT_SUCCESS;
71 }
72