From 68de78a5856f21ce40e435615904aae996c2e856 Mon Sep 17 00:00:00 2001
From: Eric Mertens <emertens@gmail.com>
Date: Sun, 4 Dec 2022 10:30:01 -0800
Subject: [PATCH] 2022-03

---
 2022/03.cpp         | 92 +++++++++++++++++++++++++++++++++++++++++++++
 2022/CMakeLists.txt |  3 ++
 2 files changed, 95 insertions(+)
 create mode 100644 2022/03.cpp

diff --git a/2022/03.cpp b/2022/03.cpp
new file mode 100644
index 0000000..752d7a9
--- /dev/null
+++ b/2022/03.cpp
@@ -0,0 +1,92 @@
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+#include <numeric>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <tuple>
+#include <vector>
+#include <string_view>
+
+#include <doctest.h>
+
+#include <aocpp/Startup.hpp>
+
+namespace {
+
+auto Parse(std::istream & in) -> std::vector<std::string>
+{
+  std::vector<std::string> result;
+  std::string line;
+  while (std::getline(in, line)) {
+    result.emplace_back(std::move(line));
+  }
+  return result;
+}
+
+auto Priority(char const c) -> std::int64_t
+{
+  return c < 'a' ? c-'A'+27 : c-'a'+1;
+}
+
+auto Intersect(std::string const& a, std::string const& b) {
+  std::string common;
+  std::set_intersection(a.begin(), a.end(), b.begin(), b.end(),
+    std::back_inserter(common));
+  return common;
+}
+
+auto Part1(std::vector<std::string> const& input) -> std::int64_t
+{
+  std::int64_t n {0};
+  for (auto const& line : input) {
+    auto m = line.size() / 2;
+
+    auto elf1 {line.substr(0, m)};
+    std::sort(elf1.begin(), elf1.end());
+
+    auto elf2 {line.substr(m)};
+    std::sort(elf2.begin(), elf2.end());
+
+    n += Priority(Intersect(elf1, elf2).at(0));
+  }
+  return n;
+}
+
+auto Part2(std::vector<std::string> input) -> std::int64_t
+{
+  std::int64_t n {0};
+
+  for (auto & line : input) {
+    std::sort(line.begin(), line.end());
+  }
+
+  for (std::size_t i = 0; i + 2 < input.size(); i += 3) {
+    n += Priority(Intersect(Intersect(input[i], input[i+1]), input[i+2]).at(0));
+  }
+  return n;
+}
+
+} // namespace
+
+TEST_SUITE("2022-03 examples") {
+  TEST_CASE("example") {
+    std::istringstream in {
+      "vJrwpWtwJgWrhcsFMMfFFhFp\n"
+      "jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL\n"
+      "PmmdzqPrVvPwwTWBwg\n"
+      "wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn\n"
+      "ttgJtRGJQctTZtZT\n"
+      "CrZsJsPPZsGzwwsLwLmpwMDw\n"};
+    auto input = Parse(in);
+    CHECK(Part1(input) == 157);
+    CHECK(Part2(std::move(input)) == 70);
+  }
+}
+
+auto main(int argc, char** argv) -> int {
+  auto input = Parse(*aocpp::Startup(argc, argv));
+  std::cout << "Part 1: " << Part1(input) << std::endl;
+  std::cout << "Part 2: " << Part2(std::move(input)) << std::endl;
+}
diff --git a/2022/CMakeLists.txt b/2022/CMakeLists.txt
index 96e23bb..d7366a4 100644
--- a/2022/CMakeLists.txt
+++ b/2022/CMakeLists.txt
@@ -1,5 +1,8 @@
 add_executable(2022_01 01.cpp)
 target_link_libraries(2022_01 aocpp)
 
+add_executable(2022_03 03.cpp)
+target_link_libraries(2022_03 aocpp)
+
 add_executable(2022_04 04.cpp)
 target_link_libraries(2022_04 aocpp)