connected_components.hpp

/*********************************************************************
 *
 * Linear Arrangement Library - A library that implements a collection
 * algorithms for linear arrangments of graphs.
 *
 * Copyright (C) 2019 - 2024
 *
 * This file is part of Linear Arrangement Library. The full code is available
 * at:
 *      https://github.com/LAL-project/linear-arrangement-library.git
 *
 * Linear Arrangement Library is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * Linear Arrangement Library is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Linear Arrangement Library.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Contact:
 *
 *     Lluís Alemany Puig (lluis.alemany.puig@upc.edu)
 *         LQMC (Quantitative, Mathematical, and Computational Linguisitcs)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/lalemany/
 *
 *     Ramon Ferrer i Cancho (rferrericancho@cs.upc.edu)
 *         LQMC (Quantitative, Mathematical, and Computational Linguisitcs)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Office 220, Omega building
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/rferrericancho/
 *
 ********************************************************************/
 
#pragma once
 
// C++ includes
#if defined DEBUG
#include <cassert>
#endif
#include <vector>
 
// lal includes
#include <lal/detail/array.hpp>
#include <lal/basic_types.hpp>
 
namespace lal {
namespace properties {
 
template <class graph_t>
class connected_components {
public:
    typedef typename std::vector<graph_t>::const_iterator const_iterator;
    typedef typename std::vector<graph_t>::iterator iterator;
 
public:
 
    [[nodiscard]] graph_t& operator[] (const std::size_t i) noexcept {
#if defined DEBUG
        assert(i < m_connected_components.size());
#endif
        return m_connected_components[i];
    }
 
    [[nodiscard]] const graph_t& operator[] (const std::size_t i) const noexcept {
#if defined DEBUG
        assert(i < m_connected_components.size());
#endif
        return m_connected_components[i];
    }
 
    /* MODIFIERS */
 
    void init(const std::size_t n) noexcept {
        m_node_to_cc.resize(n, n + 1);
        m__graph_node__to__cc_node.resize(n, n + 1);
    }
 
    void add_graph(graph_t&& g) noexcept {
        const auto n = g.get_num_nodes();
        m_connected_components.push_back(std::forward<graph_t>(g));
        m__cc_node__to__graph_node.emplace_back(n, n + 1);
    }
    void add_graph(const graph_t& g) noexcept {
        const auto n = g.get_num_nodes();
        m_connected_components.push_back(g);
        m__cc_node__to__graph_node.emplace_back(n, n + 1);
    }
 
    void set_node_cc(const node u, const std::size_t label) noexcept {
        m_node_to_cc[u] = label;
    }
 
    void set_label_graph_node_to_cc_node(const node u, const std::size_t label) noexcept {
        m__graph_node__to__cc_node[u] = label;
    }
    void set_label_cc_node_to_graph_node
    (
        const std::size_t cc_idx,
        const node u,
        const std::size_t label
    )
    noexcept
    {
        m__cc_node__to__graph_node[cc_idx][u] = label;
    }
 
    /* GETTERS */
 
    [[nodiscard]] std::size_t size() const noexcept {
        return m_connected_components.size();
    }
 
    [[nodiscard]] std::size_t get_cc_node(const node u) const noexcept {
        return m_node_to_cc[u];
    }
 
    [[nodiscard]] std::size_t get_label_graph_node_to_cc_node(const node u)
    const noexcept
    {
        return m__graph_node__to__cc_node[u];
    }
    [[nodiscard]] std::size_t get_label_cc_node_to_graph_node
    (const std::size_t cc_idx, const node u)
    const noexcept
    {
        return m__cc_node__to__graph_node[cc_idx][u];
    }
 
    [[nodiscard]] const_iterator begin() const noexcept
    { return m_connected_components.begin(); }
    [[nodiscard]] iterator begin() noexcept
    { return m_connected_components.begin(); }
 
    [[nodiscard]] const_iterator end() const noexcept
    { return m_connected_components.end(); }
    [[nodiscard]] iterator end() noexcept
    { return m_connected_components.end(); }
 
private:
    std::vector<graph_t> m_connected_components;
 
    std::vector<detail::array<std::size_t>> m__cc_node__to__graph_node;
    detail::array<std::size_t> m__graph_node__to__cc_node;
 
    detail::array<std::size_t> m_node_to_cc;
};
 
} // -- namespace properties
} // -- namespace lal