2022-01

2022/01.cpp

@@ -0,0 +1,83 @@
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+#include <numeric>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include <doctest.h>
+
+#include <aocpp/Startup.hpp>
+
+namespace {
+
+using Input = std::vector<std::vector<std::int64_t>>;
+
+/// @brief Parse the input stream as a newline-delimited list of lists of integers
+/// @param in input file parsed until EOF
+/// @return outer list of elves, inner lists of calories
+auto Parse(std::istream & in) -> Input
+{
+  Input result {{}};
+  std::string line;
+  while (std::getline(in, line)) {
+    if (line.empty()) {
+      result.push_back({});
+    } else {
+      result.back().emplace_back(std::stoll(line));
+    }
+  }
+  return result;
+}
+
+/// @brief Compute the top calorie carrying elves
+/// @param input List of elves each with a list of calories
+/// @return top 1 and sum of top 3 calorie counts
+auto Solve(Input const& input) -> std::pair<std::int64_t, std::int64_t>
+{
+  if (input.size() < 3) { throw std::runtime_error{"bad input"}; }
+
+  std::vector<std::int64_t> elves;
+  for (auto const& elf : input) {
+    elves.push_back(std::reduce(elf.begin(), elf.end()));
+  }
+
+  std::partial_sort(elves.begin(), std::next(elves.begin(), 3), elves.end(), std::greater());
+
+  return {elves.front(), std::reduce(elves.begin(), std::next(elves.begin(), 3))};
+}
+
+} // namespace
+
+TEST_SUITE("2022-01 examples") {
+  TEST_CASE("example") {
+    std::istringstream in {
+      "1000\n"
+      "2000\n"
+      "3000\n"
+      "\n"
+      "4000\n"
+      "\n"
+      "5000\n"
+      "6000\n"
+      "\n"
+      "7000\n"
+      "8000\n"
+      "9000\n"
+      "\n"
+      "10000\n"};
+    auto entries = Parse(in);
+    auto [p1,p2] = Solve(entries);
+    CHECK(p1 == 24000);
+    CHECK(p2 == 45000);
+  }
+}
+
+auto main(int argc, char** argv) -> int {
+  auto [p1,p2] = Solve(Parse(*aocpp::Startup(argc, argv)));
+  std::cout << "Part 1: " << p1 << std::endl;
+  std::cout << "Part 2: " << p2 << std::endl;
+}

2022/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(2022_01 01.cpp)
+target_link_libraries(2022_01 aocpp)

CMakeLists.txt

@@ -28,3 +28,4 @@ add_subdirectory(2017)
 add_subdirectory(2018)
 add_subdirectory(2019)
 add_subdirectory(2020)
+add_subdirectory(2022)