all_lab_rooted_trees.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
 
// lal includes
#include <lal/graphs/rooted_tree.hpp>
#include <lal/generate/all_lab_free_trees.hpp>
#include <lal/generate/tree_generator.hpp>
 
namespace lal {
namespace generate {
 
class all_lab_rooted_trees : public _tree_generator<graphs::rooted_tree> {
public:
    /* CONSTRUCTORS */
 
    all_lab_rooted_trees() noexcept : _tree_generator<graphs::rooted_tree>() { }
 
    all_lab_rooted_trees(uint64_t n) noexcept {
        init(n);
    }
    all_lab_rooted_trees(const all_lab_rooted_trees& Gen) noexcept = default;
 
    all_lab_rooted_trees(all_lab_rooted_trees&& Gen) noexcept = default;
 
    ~all_lab_rooted_trees() = default;
 
    all_lab_rooted_trees& operator= (const all_lab_rooted_trees& g) noexcept = default;
    all_lab_rooted_trees& operator= (all_lab_rooted_trees&& g) noexcept = default;
 
    /* INITIALIZE */
 
    void init(uint64_t n) noexcept {
        _tree_generator::init(n);
        m_gen_lab_free_tree.init(m_n);
        reset();
    }
 
    void clear() noexcept {
        _tree_generator::clear();
        m_cur_ftree.clear();
        m_gen_lab_free_tree.clear();
    }
 
    /* GETTERS */
 
    [[nodiscard]] bool end() const noexcept { return m_reached_end; }
 
    [[nodiscard]] node get_current_root() const noexcept { return m_cur_root; }
 
    /* MODIFIERS */
 
    void next() noexcept {
        if (not has_next() or m_reached_end) {
            m_reached_end = true;
            return;
        }
 
        // m_n > 1
        if (m_cur_root < m_n - 1) {
            ++m_cur_root;
        }
        else {
            m_cur_root = 0;
            m_cur_ftree = m_gen_lab_free_tree.get_tree();
            m_gen_lab_free_tree.next();
        }
    }
 
    void reset() noexcept {
        activate_all_postprocessing_actions();
        __reset();
        next();
    }
 
    [[nodiscard]] bool has_next() const noexcept {
        return m_cur_root + 1 < m_n or not m_gen_lab_free_tree.end();
    }
 
    [[nodiscard]] graphs::rooted_tree yield_tree() noexcept {
        const auto t = get_tree();
        next();
        return t;
    }
 
protected:
    [[nodiscard]] graphs::rooted_tree __get_tree() noexcept {
#if defined DEBUG
        assert(m_cur_root < m_n);
#endif
        return graphs::rooted_tree(m_cur_ftree, m_cur_root);
    }
 
    void __reset() noexcept {
        m_reached_end = false;
        // so that in the next call the root is set to 0
        m_cur_root = m_n - 1;
        // the labeled free tree generator now points to the first tree
        m_gen_lab_free_tree.reset();
        // deactivate all postprocessing of the free tree
        m_gen_lab_free_tree.deactivate_all_postprocessing_actions();
    }
 
private:
    all_lab_free_trees m_gen_lab_free_tree;
    graphs::free_tree m_cur_ftree;
    node m_cur_root;
    bool m_reached_end = false;
};
 
} // -- namespace generate
} // -- namespace lal