From f5f1680de37b151833e29aa1b708c54c871d4e3f Mon Sep 17 00:00:00 2001
From: Eric Mertens <emertens@galois.com>
Date: Mon, 23 Jan 2023 22:37:02 -0500
Subject: [PATCH] 2022-06

---
 2022/06.cpp         | 67 +++++++++++++++++++++++++++++++++++++++++++++
 2022/CMakeLists.txt |  3 ++
 2 files changed, 70 insertions(+)
 create mode 100644 2022/06.cpp

diff --git a/2022/06.cpp b/2022/06.cpp
new file mode 100644
index 0000000..60b5bdc
--- /dev/null
+++ b/2022/06.cpp
@@ -0,0 +1,67 @@
+#include <algorithm>
+#include <array>
+#include <cstdint>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+#include <limits>
+
+#include <doctest.h>
+
+#include <aocpp/Startup.hpp>
+
+namespace {
+
+auto Solve(std::string const& input, std::size_t n) -> std::size_t
+{
+  std::array<std::size_t, 256> counts {};
+  std::size_t uniques {0};
+
+  auto const inc = [&](char c) {
+    if (0 == counts[static_cast<std::uint8_t>(c)]++) {
+      uniques++;
+    }
+  };
+
+  auto const dec = [&](char c) {
+    if (0 == --counts[static_cast<std::uint8_t>(c)]) {
+      uniques--;
+    }
+  };
+
+  for (std::size_t i = 0; i < n; ++i) {
+    inc(input[i]);
+  }
+
+  for (std::size_t i = n; i < input.size(); ++i) {
+    dec(input[i-n]);
+    inc(input[i]);
+    if (uniques == n) { return i+1; }
+  }
+
+  throw std::runtime_error{"bad input"};
+}
+
+} // namespace
+
+TEST_SUITE("2022-06 examples") {
+  TEST_CASE("examples") {
+    CHECK(Solve("bvwbjplbgvbhsrlpgdmjqwftvncz", 4) == 5);
+    CHECK(Solve("nppdvjthqldpwncqszvftbrmjlhg", 4) == 6);
+    CHECK(Solve("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", 4) == 10);
+    CHECK(Solve("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", 4) == 11);
+
+    CHECK(Solve("mjqjpqmgbljsphdztnvjfqwrcgsmlb", 14) == 19);
+    CHECK(Solve("bvwbjplbgvbhsrlpgdmjqwftvncz", 14) == 23);
+    CHECK(Solve("nppdvjthqldpwncqszvftbrmjlhg", 14) == 23);
+    CHECK(Solve("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", 14) == 29);
+    CHECK(Solve("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", 14) == 26);
+  }
+}
+
+auto main(int argc, char** argv) -> int {
+  std::string input;
+  std::getline(*aocpp::Startup(argc, argv), input);
+  std::cout << "Part 1: " << Solve(input, 4) << std::endl;
+  std::cout << "Part 2: " << Solve(input, 14) << std::endl;
+}
diff --git a/2022/CMakeLists.txt b/2022/CMakeLists.txt
index a291217..ec51db3 100644
--- a/2022/CMakeLists.txt
+++ b/2022/CMakeLists.txt
@@ -7,6 +7,9 @@ target_link_libraries(2022_03 aocpp)
 add_executable(2022_04 04.cpp)
 target_link_libraries(2022_04 aocpp)
 
+add_executable(2022_06 06.cpp)
+target_link_libraries(2022_06 aocpp)
+
 add_executable(2022_08 08.cpp)
 target_link_libraries(2022_08 aocpp)