1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Copyright 2009 Trustees of Indiana University.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek, Michael Hansen
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
#include <iostream>
#include <vector>
#include <boost/foreach.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graph_utility.hpp>
#include <boost/graph/incremental_components.hpp>
#include <boost/pending/disjoint_sets.hpp>
/*
This example shows how to use the disjoint set data structure
to compute the connected components of an undirected, changing
graph.
Sample output:
An undirected graph:
0 <--> 1 4
1 <--> 0 4
2 <--> 5
3 <-->
4 <--> 1 0
5 <--> 2
representative[0] = 1
representative[1] = 1
representative[2] = 5
representative[3] = 3
representative[4] = 1
representative[5] = 5
component 0 contains: 4 1 0
component 1 contains: 3
component 2 contains: 5 2
*/
using namespace boost;
int main(int argc, char* argv[])
{
typedef adjacency_list <vecS, vecS, undirectedS> Graph;
typedef graph_traits<Graph>::vertex_descriptor Vertex;
typedef graph_traits<Graph>::vertices_size_type VertexIndex;
const int VERTEX_COUNT = 6;
Graph graph(VERTEX_COUNT);
std::vector<VertexIndex> rank(num_vertices(graph));
std::vector<Vertex> parent(num_vertices(graph));
typedef VertexIndex* Rank;
typedef Vertex* Parent;
disjoint_sets<Rank, Parent> ds(&rank[0], &parent[0]);
initialize_incremental_components(graph, ds);
incremental_components(graph, ds);
graph_traits<Graph>::edge_descriptor edge;
bool flag;
boost::tie(edge, flag) = add_edge(0, 1, graph);
ds.union_set(0,1);
boost::tie(edge, flag) = add_edge(1, 4, graph);
ds.union_set(1,4);
boost::tie(edge, flag) = add_edge(4, 0, graph);
ds.union_set(4,0);
boost::tie(edge, flag) = add_edge(2, 5, graph);
ds.union_set(2,5);
std::cout << "An undirected graph:" << std::endl;
print_graph(graph, get(boost::vertex_index, graph));
std::cout << std::endl;
BOOST_FOREACH(Vertex current_vertex, vertices(graph)) {
std::cout << "representative[" << current_vertex << "] = " <<
ds.find_set(current_vertex) << std::endl;
}
std::cout << std::endl;
typedef component_index<VertexIndex> Components;
// NOTE: Because we're using vecS for the graph type, we're
// effectively using identity_property_map for a vertex index map.
// If we were to use listS instead, the index map would need to be
// explicitly passed to the component_index constructor.
Components components(parent.begin(), parent.end());
// Iterate through the component indices
BOOST_FOREACH(VertexIndex current_index, components) {
std::cout << "component " << current_index << " contains: ";
// Iterate through the child vertex indices for [current_index]
BOOST_FOREACH(VertexIndex child_index,
components[current_index]) {
std::cout << child_index << " ";
}
std::cout << std::endl;
}
return (0);
}
|
