| //======================================================================= |
| // 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); |
| } |
| |