all_bipartite_arrangements.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
 
// lal includes
#include <lal/linear_arrangement.hpp>
#include <lal/graphs/graph.hpp>
#include <lal/properties/bipartite_graph_coloring.hpp>
#include <lal/properties/bipartite_graph_colorability.hpp>
 
namespace lal {
namespace generate {
 
class all_bipartite_arrangements {
public:
 
    template <class graph_t>
    all_bipartite_arrangements(const graph_t& g) {
        static_assert(std::is_base_of_v<graphs::graph, graph_t>);
        m_coloring = properties::bipartite_coloring(g);
        init();
    }
 
    all_bipartite_arrangements(const all_bipartite_arrangements& Gen) noexcept = default;
    all_bipartite_arrangements(all_bipartite_arrangements&& Gen) noexcept = default;
 
    all_bipartite_arrangements(const properties::bipartite_graph_coloring& c) noexcept {
        m_coloring = c;
        init();
    }
    all_bipartite_arrangements(properties::bipartite_graph_coloring&& c) noexcept {
        m_coloring = std::move(c);
        init();
    }
 
    ~all_bipartite_arrangements() noexcept = default;
 
    [[nodiscard]] const linear_arrangement& get_arrangement() const noexcept
    { return m_arr; }
 
    [[nodiscard]] bool end() const noexcept { return m_do_mirror and m_reached_end_red; }
 
    void next() noexcept;
 
    void reset() noexcept {
        m_do_mirror = false;
        m_reached_end_blue = false;
        m_reached_end_red = false;
        init_arrangement(true);
    }
 
    [[nodiscard]] linear_arrangement yield_arrangement() noexcept {
        // yes, a copy...
        const linear_arrangement arr = get_arrangement();
        next();
        return arr;
    }
 
private:
    void init() noexcept;
 
    void init_arrangement(const bool red_first) noexcept;
 
private:
    bool m_do_mirror;
    bool m_reached_end_blue;
    bool m_reached_end_red;
 
    std::size_t m_n_blue;
    std::size_t m_n_red;
 
    linear_arrangement m_arr;
 
    properties::bipartite_graph_coloring m_coloring;
 
private:
    static constexpr properties::bipartite_graph_coloring::color_t blue =
        properties::bipartite_graph_coloring::blue;
    static constexpr properties::bipartite_graph_coloring::color_t red =
        properties::bipartite_graph_coloring::red;
};
 
} // -- namespace generate
} // -- namespace lal