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
main()13 int main()
14 {
15 using namespace boost;
16 typedef adjacency_list< vecS, vecS, undirectedS, no_property,
17 property< edge_weight_t, int > >
18 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), E(3, 4),
24 E(4, 0), E(4, 1) };
25 int weights[] = { 1, 1, 2, 7, 3, 1, 1, 1 };
26 std::size_t num_edges = sizeof(edge_array) / sizeof(E);
27 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
28 Graph g(num_nodes);
29 property_map< Graph, edge_weight_t >::type weightmap = get(edge_weight, g);
30 for (std::size_t j = 0; j < num_edges; ++j)
31 {
32 Edge e;
33 bool inserted;
34 boost::tie(e, inserted)
35 = add_edge(edge_array[j].first, edge_array[j].second, g);
36 weightmap[e] = weights[j];
37 }
38 #else
39 Graph g(edge_array, edge_array + num_edges, weights, num_nodes);
40 #endif
41 property_map< Graph, edge_weight_t >::type weight = get(edge_weight, g);
42 std::vector< Edge > spanning_tree;
43
44 kruskal_minimum_spanning_tree(g, std::back_inserter(spanning_tree));
45
46 std::cout << "Print the edges in the MST:" << std::endl;
47 for (std::vector< Edge >::iterator ei = spanning_tree.begin();
48 ei != spanning_tree.end(); ++ei)
49 {
50 std::cout << source(*ei, g) << " <--> " << target(*ei, g)
51 << " with weight of " << weight[*ei] << std::endl;
52 }
53
54 std::ofstream fout("figs/kruskal-eg.dot");
55 fout << "graph A {\n"
56 << " rankdir=LR\n"
57 << " size=\"3,3\"\n"
58 << " ratio=\"filled\"\n"
59 << " edge[style=\"bold\"]\n"
60 << " node[shape=\"circle\"]\n";
61 graph_traits< Graph >::edge_iterator eiter, eiter_end;
62 for (boost::tie(eiter, eiter_end) = edges(g); eiter != eiter_end; ++eiter)
63 {
64 fout << source(*eiter, g) << " -- " << target(*eiter, g);
65 if (std::find(spanning_tree.begin(), spanning_tree.end(), *eiter)
66 != spanning_tree.end())
67 fout << "[color=\"black\", label=\"" << get(edge_weight, g, *eiter)
68 << "\"];\n";
69 else
70 fout << "[color=\"gray\", label=\"" << get(edge_weight, g, *eiter)
71 << "\"];\n";
72 }
73 fout << "}\n";
74 return EXIT_SUCCESS;
75 }
76