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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 18:24:20 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 18:24:20 +0000
commit483eb2f56657e8e7f419ab1a4fab8dce9ade8609 (patch)
treee5d88d25d870d5dedacb6bbdbe2a966086a0a5cf /src/boost/libs/graph/example/incremental_components.cpp
parentInitial commit. (diff)
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Adding upstream version 14.2.21.upstream/14.2.21upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+//=======================================================================
+// 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);
+}
+