1 //=======================================================================
2 // Copyright 1997-2001 University of Notre Dame.
3 // Authors: Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee
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
10 #error \
11 "This example appears to be incorrect; it uses edge weights that are smaller than 0 using the comparison operator passed to Dijkstra's algorithm, which is not allowed."
12
13 #include <boost/config.hpp>
14 #include <iostream>
15
16 #include <boost/graph/graph_traits.hpp>
17 #include <boost/graph/graph_utility.hpp>
18 #include <boost/graph/adjacency_list.hpp>
19 #include <boost/graph/dijkstra_shortest_paths.hpp>
20 #include <boost/graph/visitors.hpp>
21 #include <boost/graph/transpose_graph.hpp>
22
23 /* Output:
24
25 distances from start vertex:
26 distance(a) = 0
27 distance(b) = 3
28 distance(c) = 1
29 distance(d) = 3
30 distance(e) = 3
31
32 min-max paths tree
33 a --> c
34 b -->
35 c --> d
36 d --> e
37 e --> b
38
39 */
40
main(int,char * [])41 int main(int, char*[])
42 {
43 using namespace boost;
44
45 typedef adjacency_list< listS, vecS, directedS, no_property,
46 property< edge_weight_t, int > >
47 Graph;
48 typedef graph_traits< Graph >::vertex_descriptor Vertex;
49
50 typedef std::pair< int, int > E;
51
52 const char name[] = "abcdef";
53
54 const int num_nodes = 6;
55 E edges[] = { E(0, 2), E(1, 1), E(1, 3), E(1, 4), E(2, 1), E(2, 3), E(3, 4),
56 E(4, 0), E(4, 1) };
57 int weights[] = { 1, 2, 1, 2, 7, 3, 1, 1, 1 };
58 const int n_edges = sizeof(edges) / sizeof(E);
59 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
60 // VC++ can't handle iterator constructors
61 Graph G(num_nodes);
62 property_map< Graph, edge_weight_t >::type weightmap = get(edge_weight, G);
63 for (std::size_t j = 0; j < sizeof(edges) / sizeof(E); ++j)
64 {
65 graph_traits< Graph >::edge_descriptor e;
66 bool inserted;
67 boost::tie(e, inserted) = add_edge(edges[j].first, edges[j].second, G);
68 weightmap[e] = weights[j];
69 }
70 #else
71 Graph G(edges, edges + n_edges, weights, num_nodes);
72 property_map< Graph, edge_weight_t >::type weightmap = get(edge_weight, G);
73 #endif
74
75 std::vector< Vertex > p(num_vertices(G));
76 std::vector< int > d(num_vertices(G));
77
78 Vertex s = *(vertices(G).first);
79
80 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
81 dijkstra_shortest_paths(G, s, &p[0], &d[0], weightmap, get(vertex_index, G),
82 std::greater< int >(), closed_plus< int >(),
83 (std::numeric_limits< int >::max)(), 0, default_dijkstra_visitor());
84 #else
85 dijkstra_shortest_paths(G, s,
86 distance_map(&d[0]).predecessor_map(&p[0]).distance_compare(
87 std::greater< int >()));
88 #endif
89
90 std::cout << "distances from start vertex:" << std::endl;
91 graph_traits< Graph >::vertex_iterator vi, vend;
92 for (boost::tie(vi, vend) = vertices(G); vi != vend; ++vi)
93 std::cout << "distance(" << name[*vi] << ") = " << d[*vi] << std::endl;
94 std::cout << std::endl;
95
96 std::cout << "min-max paths tree" << std::endl;
97 adjacency_list<> tree(num_nodes);
98
99 for (boost::tie(vi, vend) = vertices(G); vi != vend; ++vi)
100 if (*vi != p[*vi])
101 add_edge(p[*vi], *vi, tree);
102
103 print_graph(tree, name);
104
105 return 0;
106 }
107