/******************************************************************************* * * Copyright (c) 2020 Gnarwhal * * ----------------------------------------------------------------------------- * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files(the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * *******************************************************************************/ #include #include #include #include #include #include "../misc/types.hpp" #include "../misc/print.hpp" constexpr auto CUP_COUNT = 9; auto day23() -> void { auto start = usize(0); auto nums = std::array(); auto big_nums = std::vector(1000000); { auto line = std::string(); auto file = std::ifstream("inputs/day23.input"); getline(file, line); for (auto i = usize(0); i < CUP_COUNT; ++i) { nums[line[i] - '1'] = line[(i + 1) % CUP_COUNT] - '1'; } start = line[0] - '1'; for (auto i = usize(0); i < CUP_COUNT; ++i) { if (nums[i] != start) { big_nums[i] = nums[i]; } else { big_nums[i] = CUP_COUNT; } } for (auto i = CUP_COUNT; i < big_nums.size() - 1; ++i) { big_nums[i] = i + 1; } big_nums[big_nums.size() - 1] = start; } auto begin = usize(0); auto end = usize(0); // Part 1 auto current = start; for (auto i = usize(0); i < 100; ++i) { begin = nums[current]; end = nums[nums[begin]]; nums[current] = nums[end]; auto destination = current; while ( begin == (destination = (destination + CUP_COUNT - 1) % CUP_COUNT) || nums[begin] == destination || end == destination ); nums[end] = nums[destination]; nums[destination] = begin; current = nums[current]; } auto out = std::array{ 0 }; for (auto i = nums[0], j = usize(0); i != 0; i = nums[i], ++j) { out[j] = (i + '1'); } print(&out[0]); // Part 2 current = start; for (auto i = usize(0); i < 10000000; ++i) { begin = big_nums[current]; end = big_nums[big_nums[begin]]; big_nums[current] = big_nums[end]; auto destination = current; while ( begin == (destination = (destination + big_nums.size() - 1) % big_nums.size()) || big_nums[begin] == destination || end == destination ); big_nums[end] = big_nums[destination]; big_nums[destination] = begin; current = big_nums[current]; } print(((big_nums[0] + 1) * (big_nums[big_nums[0]] + 1))); }