#ifndef COMP6771_WORD_LADDER_H
#define COMP6771_WORD_LADDER_H

#include <algorithm>
#include <filesystem>
#include <fstream>
#include <numeric>
#include <queue>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

namespace word_ladder {
// Given a file path to a newline-separated list of words...
// Loads those words into an unordered set and returns it.
auto read_lexicon(const std::string& path) -> std::unordered_set<std::string>;

// Given a start word and destination word, returns all the shortest possible
// paths from the start word to the destination, where each word in an
// individual path is a valid word per the provided lexicon. Preconditions:
// - from.size() == to.size()
// - lexicon.contains(from)
// - lexicon.contains(to)
auto generate(const std::string& from, const std::string& to,
              const std::unordered_set<std::string>& lexicon)
    -> std::vector<std::vector<std::string>>;
}  // namespace word_ladder

#endif  // COMP6771_WORD_LADDER_H