121 lines
3.4 KiB
C++
121 lines
3.4 KiB
C++
//=======================================================================
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// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
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// Copyright 2009 Trustees of Indiana University.
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// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek, Michael Hansen
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//=======================================================================
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#include <iostream>
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#include <vector>
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#include <boost/foreach.hpp>
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#include <boost/graph/adjacency_list.hpp>
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#include <boost/graph/graph_utility.hpp>
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#include <boost/graph/incremental_components.hpp>
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#include <boost/pending/disjoint_sets.hpp>
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/*
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This example shows how to use the disjoint set data structure
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to compute the connected components of an undirected, changing
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graph.
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Sample output:
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An undirected graph:
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0 <--> 1 4
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1 <--> 0 4
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2 <--> 5
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3 <-->
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4 <--> 1 0
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5 <--> 2
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representative[0] = 1
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representative[1] = 1
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representative[2] = 5
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representative[3] = 3
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representative[4] = 1
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representative[5] = 5
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component 0 contains: 4 1 0
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component 1 contains: 3
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component 2 contains: 5 2
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*/
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using namespace boost;
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int main(int argc, char* argv[])
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{
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typedef adjacency_list< vecS, vecS, undirectedS > Graph;
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typedef graph_traits< Graph >::vertex_descriptor Vertex;
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typedef graph_traits< Graph >::vertices_size_type VertexIndex;
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const int VERTEX_COUNT = 6;
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Graph graph(VERTEX_COUNT);
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std::vector< VertexIndex > rank(num_vertices(graph));
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std::vector< Vertex > parent(num_vertices(graph));
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typedef VertexIndex* Rank;
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typedef Vertex* Parent;
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disjoint_sets< Rank, Parent > ds(&rank[0], &parent[0]);
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initialize_incremental_components(graph, ds);
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incremental_components(graph, ds);
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graph_traits< Graph >::edge_descriptor edge;
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bool flag;
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boost::tie(edge, flag) = add_edge(0, 1, graph);
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ds.union_set(0, 1);
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boost::tie(edge, flag) = add_edge(1, 4, graph);
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ds.union_set(1, 4);
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boost::tie(edge, flag) = add_edge(4, 0, graph);
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ds.union_set(4, 0);
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boost::tie(edge, flag) = add_edge(2, 5, graph);
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ds.union_set(2, 5);
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std::cout << "An undirected graph:" << std::endl;
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print_graph(graph, get(boost::vertex_index, graph));
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std::cout << std::endl;
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BOOST_FOREACH (Vertex current_vertex, vertices(graph))
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{
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std::cout << "representative[" << current_vertex
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<< "] = " << ds.find_set(current_vertex) << std::endl;
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}
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std::cout << std::endl;
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typedef component_index< VertexIndex > Components;
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// NOTE: Because we're using vecS for the graph type, we're
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// effectively using identity_property_map for a vertex index map.
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// If we were to use listS instead, the index map would need to be
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// explicitly passed to the component_index constructor.
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Components components(parent.begin(), parent.end());
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// Iterate through the component indices
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BOOST_FOREACH (VertexIndex current_index, components)
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{
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std::cout << "component " << current_index << " contains: ";
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// Iterate through the child vertex indices for [current_index]
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BOOST_FOREACH (VertexIndex child_index, components[current_index])
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{
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std::cout << child_index << " ";
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}
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std::cout << std::endl;
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}
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return (0);
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}
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