diff --git a/2023/puzzle-13-02.cc b/2023/puzzle-13-02.cc new file mode 100644 index 0000000..7be9a58 --- /dev/null +++ b/2023/puzzle-13-02.cc @@ -0,0 +1,119 @@ +#include +#include +#include +#include +#include +#include + +using UInt = std::uint64_t; + +auto has_smidge(std::string_view row1, std::string_view row2) -> bool +{ + assert(row1.size() == row2.size()); + UInt diff_count{0}; + for (auto it1{row1.begin()}, it2{row2.begin()}; it1 != row1.end(); ++it1, ++it2) { + diff_count += static_cast(*it1 != *it2); + } + return diff_count == 1; +} + +struct Grid +{ + void clear() { rows_.clear(); } + void push_back(std::string const& row) { rows_.push_back(row); } + + [[nodiscard]] auto reflection_point(UInt const skip_row = 0) const -> UInt + { + for (std::size_t row{0}; row < rows_.size() - 1; ++row) { + if (row + 1 == skip_row) { continue; } + auto top{row}; + auto bottom{row + 1}; + while (rows_[top] == rows_[bottom]) { + if (top == 0 || bottom == rows_.size() - 1) { return row + 1; } + --top; + ++bottom; + } + } + + return 0; + } + + [[nodiscard]] auto find_smidge() const -> UInt + { + auto const skip_row{reflection_point()}; + + for (std::size_t row{0}; row < rows_.size() - 1; ++row) { + for (std::size_t row2{row + 1}; row2 < rows_.size(); ++row2) { + if (has_smidge(rows_[row], rows_[row2])) { + Grid temp(*this); + temp.rows_[row2] = temp.rows_[row]; + + if (auto const reflection_point = temp.reflection_point(skip_row); + reflection_point != 0) { + std::cout << "Found smidge between rows " << row << " and " << row2 << ". Score: " << + reflection_point << " Skip row: " << skip_row << '\n'; + for (std::size_t i{0}; i < rows_.size(); ++i) { + std::cout << rows_[i]; + if (i == row || i == row2) { std::cout << " <<<"; } + std::cout << '\n'; + } + return reflection_point; + } + } + } + } + + std::cout << "No smidge point.\n"; + return 0; + } + + [[nodiscard]] auto rotate_right() const -> Grid + { + std::cout << "Rotate right\n"; + Grid new_grid; + new_grid.rows_.resize(rows_.front().size()); + for (auto row{rows_.rbegin()}; row != rows_.rend(); ++row) { + for (std::size_t i{0}; i < row->size(); ++i) { + new_grid.rows_[i].push_back(row->at(i)); + } + } + + return new_grid; + } + +private: + std::vector rows_; +}; + +auto main() -> int try { + std::string line; + + Grid grid; + UInt rows{0}; + UInt cols{0}; + while (std::getline(std::cin, line)) { + if (line.empty()) { + rows += grid.find_smidge(); + grid = grid.rotate_right(); + cols += grid.find_smidge(); + grid.clear(); + std::cout << "CLEAR\n"; + } + else { + grid.push_back(line); + } + } + + rows += grid.find_smidge(); + grid = grid.rotate_right(); + cols += grid.find_smidge(); + + std::cout << "Columns to left: " << cols << '\n' << "Rows above: " << rows << '\n' << "Score: " << + cols + (rows * 100) << '\n'; + + return EXIT_SUCCESS; +} +catch (...) { + std::cerr << "Uncaught exception.\n"; + return EXIT_FAILURE; +}