95 lines
2.9 KiB
C++
95 lines
2.9 KiB
C++
//=======================================================================
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// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
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// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
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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 <boost/config.hpp>
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#include <iostream>
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#include <iterator>
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#include <vector>
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#include <algorithm>
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#include <utility>
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#include <boost/graph/edge_list.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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#include <boost/utility.hpp>
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#include <boost/graph/graph_utility.hpp>
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/*
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This example demonstrates the usage of the
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connected_components_on_edgelist algorithm. This differs from the
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connect_components algorithm in that the graph object
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only needs to provide access to the "list" of edges (via the
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edges() function).
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The example graphs come from "Introduction to
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Algorithms", Cormen, Leiserson, and Rivest p. 87 (though we number
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the vertices from zero instead of one).
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Sample output:
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An undirected graph (edge list):
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(0,1) (1,4) (4,0) (2,5)
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Total number of components: 3
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Vertex 0 is in the component who's representative is 1
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Vertex 1 is in the component who's representative is 1
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Vertex 2 is in the component who's representative is 5
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Vertex 3 is in the component who's representative is 3
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Vertex 4 is in the component who's representative is 1
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Vertex 5 is in the component who's representative is 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 std;
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using boost::tie;
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int main(int , char* [])
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{
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using namespace boost;
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typedef int Index; // ID of a Vertex
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typedef pair<Index,Index> Edge;
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const int N = 6;
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const int E = 4;
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Edge edgelist[] = { Edge(0, 1), Edge(1, 4), Edge(4, 0), Edge(2, 5) };
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edge_list<Edge*,Edge,ptrdiff_t,std::random_access_iterator_tag> g(edgelist, edgelist + E);
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cout << "An undirected graph (edge list):" << endl;
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print_edges(g, identity_property_map());
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cout << endl;
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disjoint_sets_with_storage<> ds(N);
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incremental_components(g, ds);
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component_index<int> components(&ds.parents()[0],
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&ds.parents()[0] + ds.parents().size());
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cout << "Total number of components: " << components.size() << endl;
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for (int k = 0; k != N; ++k)
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cout << "Vertex " << k << " is in the component who's representative is "
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<< ds.find_set(k) << endl;
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cout << endl;
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for (std::size_t i = 0; i < components.size(); ++i) {
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cout << "component " << i << " contains: ";
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component_index<int>::component_iterator
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j = components[i].first,
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jend = components[i].second;
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for ( ; j != jend; ++j)
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cout << *j << " ";
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cout << endl;
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}
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return 0;
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}
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