// Solutions to the Advent Of Code 2024.
// Copyright (C) 2025  Stefan Müller
//
// 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/>.

#pragma once

#include <map>
#include <string>
#include <vector>

class LinenTowelPatterns
{
public:
    LinenTowelPatterns();
    void add(const std::string& towelPattern);
    int64_t countArrangements(const std::string& design);
private:
    /// <summary>
    /// Tree data structure of all valid towel patterns. Each element is a vertex in the tree and represents a stripe in
    /// a towel pattern given by 's = i mod n', where 's' is the unique index offset of the stripe as defined in
    /// 'stripes_', 'i' is the index of the element, and 'n' is the number of stripes, i.e. the 'stripes_.size()'.
    /// The first value of each element indicates the next set of stripes to continue the pattern accumulated by
    /// following the path in the tree. If it is 0, this element is a leaf, and the pattern does not continue.
    /// Otherwise, it is the index of its first of 'n' children, which are contiguous in the vector. The second value of
    /// each element indicates whether there is a towel with the pattern ending at this element.
    /// </summary>
    std::vector<std::pair<size_t, bool>> patterns_;
    /// <summary>
    /// Maps stripes (represented by chars) to an index offset in the tree of towel patterns.
    /// </summary>
    std::map<char, size_t> stripes_;
    void addBranch();
};