aoc24: day02b complete

2024-12-08 22:35:49 +01:00
parent 5c692fe727
commit a1d5d359f2
14 changed files with 342 additions and 148 deletions
--- a/sol/24/day02.cpp
+++ b/sol/24/day02.cpp
@@ -0,0 +1,104 @@
+#include <fstream>
+#include <vector>
+#include <algorithm>
+#include <ranges>
+#include <numeric>
+#include <cmath>
+#include <utility>
+
+#include "aoc.hpp"
+#include "aoc/utils.hpp"
+#include "fmt/format.h"
+
+using namespace std::string_view_literals;
+using namespace aoc::types;
+
+auto part_a(std::vector<std::vector<i32>> const& reports) -> void {
+    auto const diffvec = reports | std::views::transform([](auto const& levels) {
+        return levels | std::views::adjacent_transform<2>([](auto const& a, auto const& b) {
+                            return b - a;
+                        }) | std::ranges::to<std::vector>();
+    }) | std::ranges::to<std::vector>();
+
+    auto answer = diffvec | std::views::filter([](auto const& levels) {
+        auto const n = std::ranges::all_of(levels, [](auto v) { return v < 0; });
+        auto const p = std::ranges::all_of(levels, [](auto v) { return v > 0; });
+        auto const c = std::ranges::all_of(levels, [](auto v) { return std::abs(v) > 0 && std::abs(v) <= 3; });
+        return (n || p) && c;
+    });
+
+    auto const sum = std::ranges::distance(answer);
+    fmt::print("Part A: {}\n", sum);
+
+}
+
+auto part_b(std::vector<std::vector<i32>> const& reports) -> void {
+    auto const diffvec = reports | std::views::transform([](auto const& levels) {
+        return levels | std::views::adjacent_transform<2>([](auto const& a, auto const& b) {
+                            return b - a;
+                        }) | std::ranges::to<std::vector>();
+    }) | std::ranges::to<std::vector>();
+
+    auto const test_rule = [](std::vector<i32> const& levels) {
+        auto const n = std::ranges::all_of(levels, [](auto v) { return v < 0; });
+        auto const p = std::ranges::all_of(levels, [](auto v) { return v > 0; });
+        auto const c = std::ranges::all_of(levels, [](auto v) { return std::abs(v) > 0 && std::abs(v) <= 3; });
+        return (n || p) && c;
+    };
+
+    auto nochange = diffvec | std::views::filter(test_rule);
+
+    auto unmet = std::views::zip(reports, diffvec) | std::views::filter([](auto const& vecs) {
+        auto const& [levels, diffs] = vecs;
+        auto const n = std::ranges::all_of(diffs, [](auto v) { return v < 0; });
+        auto const p = std::ranges::all_of(diffs, [](auto v) { return v > 0; });
+        auto const c = std::ranges::all_of(diffs, [](auto v) { return std::abs(v) > 0 && std::abs(v) <= 3; });
+        return !(n || p) || !c;
+    }) | std::views::transform([](auto const& vecs) {
+        auto const& [levels, diffs] = vecs;
+        return levels;
+     });
+
+    auto refit = unmet | std::views::filter([&test_rule](auto const& levels) {
+        std::vector<i32> vec{};
+        for (std::size_t i = 0; i < levels.size(); ++i) {
+            vec = levels;
+            vec.erase(std::begin(vec) + std::ptrdiff_t(i));
+            vec = vec
+                | std::views::adjacent_transform<2>([](auto const& a, auto const& b) { return b - a; })
+                | std::ranges::to<std::vector>();
+            if (test_rule(vec)) return true;
+        }
+        return false;
+    });
+
+    auto const first = std::ranges::distance(nochange);
+    auto const second = std::ranges::distance(refit);
+
+    fmt::print("Part B: {}\n", first + second);
+
+}
+
+auto aoc24::day02([[maybe_unused]]std::span<char const*> const& args) -> std::expected<void, aoc::error> {
+    auto txtres = aoc::read_text("./dat/24/re/02.txt");
+    // auto txtres = aoc::read_text("./dat/24/ex/02.txt");
+    if (!txtres) return std::unexpected(txtres.error());
+    auto const txt = *txtres;
+
+    auto const reports = txt | std::views::split("\n"sv)
+                             | std::views::transform([](auto const& str) { return std::string_view(str); })
+                             | std::views::filter([](auto const& str) { return !str.empty(); })
+                             | std::views::transform([](auto const& str) {
+                                return str | std::views::split(" "sv)
+                                           | std::views::filter([](auto str) { return !str.empty(); })
+                                           | std::views::transform([](auto const& num_str) {
+                                                 return std::stoi(std::string(std::begin(num_str), std::end(num_str)));
+                                             })
+                                           | std::ranges::to<std::vector>();
+                             }) | std::ranges::to<std::vector>();
+
+    part_a(reports);
+    part_b(reports);
+
+    return {};
+}