undirectedgraph.h

#ifndef UNDIRECTEDGRAPH_H
#define UNDIRECTEDGRAPH_H

#include <boost/graph/adjacency_list.hpp>
#include "cgaltypedefs.h"

class UndirectedGraph {
	using BoostGraph =
	    boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS>;
	BoostGraph m_boostGraph;
	std::vector<boost::optional<BoostGraph::vertex_descriptor>> m_id_to_vd;
	std::vector<boost::optional<size_t>> m_vd_to_id;

       public:
	UndirectedGraph() {}
	UndirectedGraph(size_t numberOfNodes) {
		m_id_to_vd.resize(numberOfNodes, boost::none);
		m_vd_to_id.resize(numberOfNodes, boost::none);
	}

	bool add_edge(size_t node1, size_t node2) {
		if (!m_id_to_vd[node1]) {
			m_id_to_vd[node1] = boost::add_vertex(m_boostGraph);
			size_t vdIndex = size_t(m_id_to_vd[node1].get());
			m_vd_to_id[vdIndex] = node1;
		}
		if (!m_id_to_vd[node2]) {
			m_id_to_vd[node2] = boost::add_vertex(m_boostGraph);
			size_t vdIndex = size_t(m_id_to_vd[node2].get());
			m_vd_to_id[vdIndex] = node2;
		}
		auto p = boost::add_edge(m_id_to_vd[node1].get(),
					 m_id_to_vd[node2].get(), m_boostGraph);

		return p.second;
	}

	std::vector<size_t> getAdjacentNodes(size_t nodeIndex) const {
		std::vector<size_t> adjacentNodes;
		BoostGraph::adjacency_iterator vit, vend;
		std::tie(vit, vend) = boost::adjacent_vertices(
		    m_id_to_vd[nodeIndex].get(), m_boostGraph);

		for (auto it = vit; it != vend; it++) {
			adjacentNodes.push_back(m_vd_to_id[size_t(*it)].get());
		}

		return adjacentNodes;
	}

	size_t num_vertices() const {
		return boost::num_vertices(m_boostGraph);
	}

	size_t num_edges() const { return boost::num_edges(m_boostGraph); }
};

#endif  // UNDIRECTEDGRAPH_H