128 lines
3.1 KiB
C++
128 lines
3.1 KiB
C++
#include <span>
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#include <algorithm>
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#include <ranges>
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#include <string>
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#include <string_view>
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#include <utility>
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#include <vector>
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#include "fmt/std.h"
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#include "aoc/types.hpp"
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#include "aoc/utils.hpp"
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using namespace std::string_view_literals;
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using namespace aoc::types;
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// simple pipe for std::string by value
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template <typename F>
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auto operator|(std::string s, F&& f) -> decltype(auto) {
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return std::forward<F>(f)(std::move(s));
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}
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auto ltrim(std::string s) -> std::string {
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s.erase(
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std::begin(s),
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std::find_if(s.begin(), s.end(), [](char ch) {
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return !std::isspace(static_cast<char>(ch));
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}));
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return s;
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}
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auto rtrim(std::string s) -> std::string {
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s.erase(
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std::find_if(s.rbegin(), s.rend(), [](char ch) {
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return !std::isspace(static_cast<char>(ch));
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}).base(),
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s.end());
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return s;
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}
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auto trim(std::string s) -> std::string {
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return ltrim(rtrim(std::move(s)));
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}
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// starts at 50
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[[maybe_unused]]constexpr auto raw_str = R"(
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L68
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L30
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R48
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L5
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R60
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L55
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L1
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L99
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R14
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L82
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)";
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auto map_char_to_rotdir(char c) -> i32 {
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switch (c) {
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case 'L': return -1;
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case 'R':
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default: return 1;
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}
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}
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static auto entry([[maybe_unused]]std::span<char const*> const& args) -> void {
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// std::string str{raw_str};
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auto str = aoc::read_text("./input.txt").value_or("");
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str = str | trim;
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auto rot_vec = str | std::views::split("\n"sv) | std::views::transform([](auto const& str) {
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return i32(std::stoi(std::string{++std::begin(str), std::end(str)})) * map_char_to_rotdir(*std::begin(str));
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}) | std::ranges::to<std::vector>();
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i32 start = 50;
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i32 zero_cross = 0;
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// auto sum = std::ranges::fold_left(rot_vec, 0, [&](auto a, auto t) {
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// auto const p = start;
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// start = (100 + p - t) % 100;
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//
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// zero_cross += (std::abs((p - t + 1) % 100) + std::abs(t)) / 100;
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//
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// fmt::print("pos: {}, next: {}, t: {}\n", p, start, t);
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//
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// if (start == 0) {
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// a += 1;
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// }
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//
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// return a;
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// });
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auto sum = std::ranges::fold_left(rot_vec, 0, [&](auto a, auto t) {
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auto const dir = t < 0 ? -1 : 1;
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auto const steps = std::abs(t);
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for (i32 i = 0; i < steps; ++i) {
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auto next = start + dir;
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if (next < 0) next = 99;
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next = next % 100;
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if (next % 100 == 0)
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++zero_cross;
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start = next;
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}
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if (start % 100 == 0) {
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++a;
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if (zero_cross > 0)
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zero_cross -= 1;
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}
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return a;
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});
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fmt::print("res: {}, {} sum = {}\n", sum, zero_cross, sum + zero_cross);
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}
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auto main([[maybe_unused]]int argc, [[maybe_unused]]char const* argv[]) -> int {
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try {
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entry({argv, std::next(argv, argc)});
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} catch (std::exception const& e) {
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fmt::print(stderr, "{}\n", e.what());
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return 1;
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}
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return 0;
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}
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