lca_lookup.hpp

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#ifndef GENESIS_TREE_FUNCTION_LCA_LOOKUP_H_
#define GENESIS_TREE_FUNCTION_LCA_LOOKUP_H_
 
/*
    Genesis - A toolkit for working with phylogenetic data.
    Copyright (C) 2014-2019 Lucas Czech and HITS gGmbH
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program 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 General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
    Contact:
    Lucas Czech <lucas.czech@h-its.org>
    Exelixis Lab, Heidelberg Institute for Theoretical Studies
    Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg, Germany
*/
 
#include "genesis/utils/math/range_minimum_query.hpp"
 
#include <vector>
 
namespace genesis {
namespace tree {
 
// =================================================================================================
//     Forward Declarations
// =================================================================================================
 
class Tree;
class TreeNode;
 
// =================================================================================================
//     LCA Lookup
// =================================================================================================
 
class LcaLookup
{
public:
 
    // -------------------------------------------------------------------------
    //     Construction and Rule of Five
    // -------------------------------------------------------------------------
 
    LcaLookup() = default;
    explicit LcaLookup( Tree const& tree );
 
    ~LcaLookup() = default;
 
    LcaLookup( LcaLookup const& other ) = default;
    LcaLookup( LcaLookup&& )            = default;
 
    LcaLookup& operator= ( LcaLookup const& other ) = default;
    LcaLookup& operator= ( LcaLookup&& )            = default;
 
    // -------------------------------------------------------------------------
    //     Lookup
    // -------------------------------------------------------------------------
 
    std::size_t operator()( size_t node_index_a, size_t node_index_b, size_t root_index ) const;
    TreeNode const& operator()( TreeNode const& node_a, TreeNode const& node_b, TreeNode const& root_node ) const;
 
    size_t operator()( size_t node_index_a, size_t node_index_b ) const;
    TreeNode const& operator()( TreeNode const& node_a, TreeNode const& node_b ) const;
 
    // -------------------------------------------------------------------------
    //     Internal Helper Functions
    // -------------------------------------------------------------------------
 
private:
 
    void init_( Tree const& tree );
 
    size_t eulertour_query_( size_t i, size_t j ) const;
 
    size_t lookup_( size_t node_index_a, size_t node_index_b, size_t root_index ) const;
 
    // -------------------------------------------------------------------------
    //     Data Members
    // -------------------------------------------------------------------------
 
private:
 
    utils::RangeMinimumQuery eulertour_rmq_;
 
    std::vector<size_t> eulertour_order_;
 
    std::vector<size_t> eulertour_first_occurrence_;
 
    Tree const* tree_ = nullptr;
    size_t      root_idx_;
};
 
} // namespace tree
} // namespace genesis
 
#endif // include guard