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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 18:24:20 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 18:24:20 +0000 |
commit | 483eb2f56657e8e7f419ab1a4fab8dce9ade8609 (patch) | |
tree | e5d88d25d870d5dedacb6bbdbe2a966086a0a5cf /src/boost/libs/graph/example/incremental_components.cpp | |
parent | Initial commit. (diff) | |
download | ceph-upstream.tar.xz ceph-upstream.zip |
Adding upstream version 14.2.21.upstream/14.2.21upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/boost/libs/graph/example/incremental_components.cpp')
-rw-r--r-- | src/boost/libs/graph/example/incremental_components.cpp | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/boost/libs/graph/example/incremental_components.cpp b/src/boost/libs/graph/example/incremental_components.cpp new file mode 100644 index 00000000..f8f156ef --- /dev/null +++ b/src/boost/libs/graph/example/incremental_components.cpp @@ -0,0 +1,119 @@ +//======================================================================= +// 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); +} + |