rooted_tree.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 <optional>
#include <vector>
 
// lal includes
#include <lal/linear_arrangement.hpp>
#include <lal/graphs/directed_graph.hpp>
#include <lal/graphs/tree.hpp>
#include <lal/graphs/free_tree.hpp>
 
namespace lal {
namespace graphs {
 
class rooted_tree : public directed_graph, virtual public tree {
public:
    /* CONSTRUCTORS */
 
    rooted_tree() noexcept : tree(), directed_graph() { }
    rooted_tree(const uint64_t n) noexcept {
        rooted_tree::_init(n);
    }
 
    rooted_tree(const directed_graph& t) noexcept;
 
    rooted_tree(directed_graph&& t) noexcept;
 
    rooted_tree(const rooted_tree& r) noexcept : graph(), tree(), directed_graph() {
        copy_full_rooted_tree(r);
    }
 
    rooted_tree(rooted_tree&& r) noexcept {
        move_full_rooted_tree(std::forward<rooted_tree>(r));
    }
 
    rooted_tree
    (
        const free_tree& t,
        const node r,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept
    {
        init_rooted(t, r, norm, check_norm);
    }
 
    rooted_tree
    (
        free_tree&& t,
        const node r,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept
    {
        init_rooted(std::forward<free_tree>(t), r, norm, check_norm);
    }
 
    ~rooted_tree() noexcept { }
 
    /* OPERATORS */
 
    rooted_tree& operator= (const rooted_tree& r) noexcept {
        copy_full_rooted_tree(r);
        return *this;
    }
    rooted_tree& operator= (rooted_tree&& r) noexcept {
        move_full_rooted_tree(std::forward<rooted_tree>(r));
        return *this;
    }
 
    /* MODIFIERS */
 
    void init_rooted
    (
        const free_tree& t,
        const node r,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    void init_rooted
    (
        free_tree&& t,
        const node r,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& add_node() noexcept {
        directed_graph::add_node();
        tree_only_add_node();
        m_size_subtrees.push_back(1);
        m_are_size_subtrees_valid = false;
        return *this;
    }
 
    rooted_tree& remove_node
    (
        const node u,
        const bool connect = false,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& add_edge
    (
        const node s,
        const node t,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& add_edge_bulk(const node s, const node t) noexcept;
 
    void finish_bulk_add(const bool norm = true, const bool check = true) noexcept;
 
    void finish_bulk_add_complete(const bool norm = true, const bool check = true) noexcept;
 
    rooted_tree& add_edges
    (
        const std::vector<edge>& edges,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& set_edges
    (
        const std::vector<edge>& edges,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& remove_edge
    (
        const node s,
        const node t,
        const bool norm = false,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& remove_edge_bulk(const node s, const node t) noexcept;
 
    void finish_bulk_remove(const bool norm = true, const bool check = true) noexcept;
 
    void finish_bulk_remove_complete(const bool norm = true, const bool check = true) noexcept;
 
    rooted_tree& remove_edges
    (
        const std::vector<edge>& edges,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& remove_edges_incident_to
    (
        const node u,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    rooted_tree& disjoint_union(const rooted_tree& t, const bool connect_roots = true)
    noexcept;
 
    void calculate_size_subtrees() noexcept;
 
    void calculate_tree_type() noexcept;
 
    /* SETTERS */
 
    void set_root(const node r) noexcept {
        // if the tree is empty simply consider it has a root...
        // although it really doesn't
 
        if (get_num_nodes() > 0) {
#if defined DEBUG
            assert(has_node(r));
            assert(is_root_valid(r));
#endif
            m_root = r;
        }
        m_are_size_subtrees_valid = false;
        tree_only_invalidate();
    }
 
    /* GETTERS */
 
    [[nodiscard]] bool is_root_valid(const node r) const noexcept {
#if defined DEBUG
        assert(has_node(r));
#endif
        return get_in_degree(r) == 0;
    }
 
    [[nodiscard]] bool can_add_edge(const node s, const node t) const noexcept;
 
    [[nodiscard]] bool can_add_edges(const std::vector<edge>& edges) const noexcept;
 
    [[nodiscard]] bool is_rooted() const noexcept { return true; }
 
    [[nodiscard]] bool is_rooted_tree() const noexcept { return is_tree() and has_root(); }
 
    [[nodiscard]] node get_root() const noexcept {
#if defined DEBUG
        assert(has_root());
#endif
        return *m_root;
    }
    [[nodiscard]] bool has_root() const noexcept { return m_root.has_value(); }
 
    [[nodiscard]] uint64_t get_num_nodes_subtree(const node u) const noexcept {
#if defined DEBUG
        assert(has_node(u));
        assert(are_size_subtrees_valid());
#endif
        return m_size_subtrees[u];
    }
 
    [[nodiscard]] bool are_size_subtrees_valid() const noexcept
    { return m_are_size_subtrees_valid; }
 
    [[nodiscard]] std::vector<edge> get_edges_subtree(const node u, const bool relab = false)
    const noexcept;
 
    [[nodiscard]] rooted_tree get_subtree(const node u) const noexcept;
 
    [[nodiscard]] free_tree to_free_tree
    (const bool norm = true, const bool check = true)
    const noexcept;
 
    [[nodiscard]] head_vector get_head_vector(const linear_arrangement& arr = {})
    const noexcept;
 
    [[nodiscard]] bool subtree_contains_node(const node r, const node u) const noexcept;
 
    [[nodiscard]] bool are_nodes_siblings(const node u, const node v) const noexcept {
        // if one of the in-degrees is zero, then 'u' and 'v' cannot be siblings
        if (get_in_degree(u) == 0 or get_in_degree(v) == 0) {
            return false;
        }
        // two nodes are siblings when their respective parent vertices
        // are the same
        return get_in_neighbors(u)[0] == get_in_neighbors(v)[0];
    }
 
    [[nodiscard]] bool node_has_parent(const node u) const noexcept {
        return get_in_degree(u) > 0;
    }
 
    [[nodiscard]] node get_parent_node(const node u) const noexcept {
#if defined DEBUG
        assert(node_has_parent(u));
#endif
        return get_in_neighbors(u)[0];
    }
 
protected:
    std::optional<node> m_root;
 
    std::vector<uint64_t> m_size_subtrees;
    bool m_are_size_subtrees_valid = false;
 
protected:
    void _init(const uint64_t n) noexcept {
        tree::tree_only_init(n);
        directed_graph::_init(n);
        m_size_subtrees.resize(n);
        m_are_size_subtrees_valid = false;
        if (n <= 1) {
            set_root(0);
        }
    }
    void _clear() noexcept {
        tree::tree_only_clear();
        directed_graph::_clear();
        m_size_subtrees.clear();
        m_are_size_subtrees_valid = false;
    }
 
    void actions_after_add_edge(const node u, const node v) noexcept;
 
    void actions_after_add_edges(const edge_list& e) noexcept;
 
    void actions_after_add_edges_bulk() noexcept;
 
    void actions_after_remove_edge(const node u, const node v) noexcept;
 
    void actions_after_remove_edges(const edge_list& e) noexcept;
 
    void actions_after_remove_edges_bulk() noexcept;
 
    void actions_before_remove_edges_incident_to(const node u) noexcept;
 
    void actions_after_remove_node(const node u) noexcept;
 
    void update_union_find_after_add_edge
    (
        const node u,
        const node v,
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
 
    void update_union_find_after_add_edges
    (
        const edge_list& edges,
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
 
    void update_union_find_after_add_edges_bulk
    (
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
 
    void update_union_find_after_remove_edge
    (
        const node u,
        const node v,
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
    
    void update_union_find_after_remove_edges
    (
        const edge_list& edges,
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
 
    void update_union_find_after_remove_edges_bulk
    (
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
 
    void update_union_find_before_remove_incident_edges_to(
        const node u,
        uint64_t * const root_of,
        uint64_t * const root_size
    )
    const noexcept;
 
    void copy_full_rooted_tree(const rooted_tree& r) noexcept {
        // copy directed_graph class
        copy_full_directed_graph(r);
 
        // copy only tree's members
        tree_only_copy(r);
 
        // copy this class' members
        m_root = r.m_root;
        m_size_subtrees = r.m_size_subtrees;
        m_are_size_subtrees_valid = r.m_are_size_subtrees_valid;
    }
    void move_full_rooted_tree(rooted_tree&& r) noexcept {
        // move-assign directed_graph class
        move_full_directed_graph(std::forward<rooted_tree>(r));
 
        // move-assign only tree's members
        tree_only_move(std::forward<tree>(r));
 
        // move this class' members
        m_root.swap(r.m_root);
        m_size_subtrees = std::move(r.m_size_subtrees);
        m_are_size_subtrees_valid = r.m_are_size_subtrees_valid;
 
        r.m_root.reset(); // old tree cannot have a root anymore.. it's been moved!
        r.m_are_size_subtrees_valid = false;
    }
 
private:
    using directed_graph::disjoint_union;
    using directed_graph::remove_node;
};
 
} // -- namespace graphs
} // -- namespace lal