From cd4c32c2a3187f06acf88c2cd85d058c99f86b36 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 11:16:03 +0200
Subject: [PATCH 01/25] Initial set-up for 2019 AoC.

---
 2019/.gitignore        |  1 +
 2019/CMakeLists.txt    | 10 ++++++++++
 2019/src/day01.cpp     | 35 +++++++++++++++++++++++++++++++++++
 2019/src/runner.cpp    | 34 ++++++++++++++++++++++++++++++++++
 2019/src/solutions.cpp | 10 ++++++++++
 2019/src/solutions.hpp | 13 +++++++++++++
 6 files changed, 103 insertions(+)
 create mode 100644 2019/.gitignore
 create mode 100644 2019/CMakeLists.txt
 create mode 100644 2019/src/day01.cpp
 create mode 100644 2019/src/runner.cpp
 create mode 100644 2019/src/solutions.cpp
 create mode 100644 2019/src/solutions.hpp

diff --git a/2019/.gitignore b/2019/.gitignore
new file mode 100644
index 0000000..8eee68f
--- /dev/null
+++ b/2019/.gitignore
@@ -0,0 +1 @@
+cmake-build-*
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
new file mode 100644
index 0000000..d321718
--- /dev/null
+++ b/2019/CMakeLists.txt
@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 3.15)
+
+project(aoc2019)
+
+add_library(AoCSolutions src/solutions.hpp src/solutions.cpp src/day01.cpp)
+target_compile_features(AoCSolutions PUBLIC cxx_std_17)
+
+add_executable(runner src/runner.cpp)
+target_compile_features(runner PUBLIC cxx_std_17)
+target_link_libraries(runner AoCSolutions)
diff --git a/2019/src/day01.cpp b/2019/src/day01.cpp
new file mode 100644
index 0000000..af57e58
--- /dev/null
+++ b/2019/src/day01.cpp
@@ -0,0 +1,35 @@
+#include <numeric>
+#include <iterator>
+#include <vector>
+#include <unordered_set>
+#include "solutions.hpp"
+
+// Currently an implementation of 2018 day 1
+void aoc2019::day01_part1(std::istream &input, std::ostream &output) {
+    int sum = std::accumulate(std::istream_iterator<int>(input),
+                              std::istream_iterator<int>(),
+                              0);
+
+    output << sum << std::endl;
+}
+
+void aoc2019::day01_part2(std::istream &input, std::ostream &output) {
+    std::vector<int> drifts;
+    std::copy(std::istream_iterator<int>(input),
+              std::istream_iterator<int>(),
+              std::back_inserter(drifts));
+
+    int cur = 0;
+    std::unordered_set<int> seen{cur};
+    while (true) {
+        for (auto drift : drifts) {
+            cur += drift;
+            if (seen.count(cur) == 1) {
+                output << drift << std::endl;
+                return;
+            } else {
+                seen.insert(cur);
+            }
+        }
+    }
+}
diff --git a/2019/src/runner.cpp b/2019/src/runner.cpp
new file mode 100644
index 0000000..30543fd
--- /dev/null
+++ b/2019/src/runner.cpp
@@ -0,0 +1,34 @@
+#include "solutions.hpp"
+#include <iostream>
+#include <charconv>
+#include <cstring>
+
+template<typename Int, int Radix = 10>
+Int int_from_cstr(Int &value, const char *begin) {
+    const char *end = begin + std::strlen(begin);
+    auto result = std::from_chars(begin, end, value, Radix);
+    if (result.ec != std::errc()) {
+        throw std::invalid_argument("Unparseable integer");
+    }
+
+    return value;
+}
+
+int main(int argc, const char *argv[]) {
+    if (argc < 2) {
+        std::cerr << "Specify a day to run.\n";
+        return 1;
+    }
+
+    int day;
+    int_from_cstr(day, argv[1]);
+
+    const aoc2019::solution_t solution = aoc2019::get_implementation(day);
+    if (solution != nullptr) {
+        solution(std::cin, std::cout);
+        return 0;
+    } else {
+        std::cerr << "Unimplemented.\n";
+        return 1;
+    }
+}
diff --git a/2019/src/solutions.cpp b/2019/src/solutions.cpp
new file mode 100644
index 0000000..bb8fd0d
--- /dev/null
+++ b/2019/src/solutions.cpp
@@ -0,0 +1,10 @@
+#include <array>
+#include "solutions.hpp"
+
+constexpr const std::array<std::array<aoc2019::solution_t, 2>, 25> SOLUTIONS = {
+        {aoc2019::day01_part1, aoc2019::day01_part2}
+};
+
+aoc2019::solution_t aoc2019::get_implementation(int day, bool part2) {
+    return SOLUTIONS.at(day - 1).at((int) part2);
+}
diff --git a/2019/src/solutions.hpp b/2019/src/solutions.hpp
new file mode 100644
index 0000000..7ac9747
--- /dev/null
+++ b/2019/src/solutions.hpp
@@ -0,0 +1,13 @@
+#pragma once
+
+#include <iosfwd>
+
+namespace aoc2019 {
+    typedef void (*solution_t)(std::istream &, std::ostream &);
+
+    solution_t get_implementation(int day, bool part2 = false);
+
+    // Declarations of all implemented days.
+    void day01_part1(std::istream &input, std::ostream &output);
+    void day01_part2(std::istream &input, std::ostream &output);
+}

From 62f3e4c5de28349daa5b161b766317d7f19e64c9 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 11:43:46 +0200
Subject: [PATCH 02/25] Improve command line parser.

---
 2019/CMakeLists.txt |  4 ++-
 2019/src/runner.cpp | 60 ++++++++++++++++++++++++++++-----------------
 2 files changed, 40 insertions(+), 24 deletions(-)

diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index d321718..f09fe54 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -2,9 +2,11 @@ cmake_minimum_required(VERSION 3.15)
 
 project(aoc2019)
 
+find_package(Boost REQUIRED COMPONENTS program_options)
+
 add_library(AoCSolutions src/solutions.hpp src/solutions.cpp src/day01.cpp)
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
 
 add_executable(runner src/runner.cpp)
 target_compile_features(runner PUBLIC cxx_std_17)
-target_link_libraries(runner AoCSolutions)
+target_link_libraries(runner AoCSolutions Boost::program_options)
diff --git a/2019/src/runner.cpp b/2019/src/runner.cpp
index 30543fd..e07fb05 100644
--- a/2019/src/runner.cpp
+++ b/2019/src/runner.cpp
@@ -1,34 +1,48 @@
 #include "solutions.hpp"
 #include <iostream>
-#include <charconv>
-#include <cstring>
+#include <boost/program_options.hpp>
 
-template<typename Int, int Radix = 10>
-Int int_from_cstr(Int &value, const char *begin) {
-    const char *end = begin + std::strlen(begin);
-    auto result = std::from_chars(begin, end, value, Radix);
-    if (result.ec != std::errc()) {
-        throw std::invalid_argument("Unparseable integer");
-    }
+namespace po = boost::program_options;
 
-    return value;
+struct AoCOptions {
+    int day;
+    bool part2;
+};
+
+AoCOptions parse_options(const int argc, const char* argv[]) {
+    AoCOptions options{};
+    po::options_description desc("Allowed options");
+    desc.add_options()
+            ("day", po::value<int>(&options.day)->required(), "The day to run.")
+            ("part2,2", po::bool_switch(&options.part2), "Whether to run part 2.");
+
+    po::positional_options_description positionals;
+    positionals.add("day", 1);
+
+    po::variables_map vm;
+
+    po::store(po::command_line_parser(argc, argv).options(desc).positional(positionals).run(), vm);
+    po::notify(vm);
+
+    return options;
 }
 
 int main(int argc, const char *argv[]) {
-    if (argc < 2) {
-        std::cerr << "Specify a day to run.\n";
+    try {
+        const auto options = parse_options(argc, argv);
+
+        const aoc2019::solution_t solution = aoc2019::get_implementation(options.day, options.part2);
+        if (solution != nullptr) {
+            solution(std::cin, std::cout);
+            return 0;
+        } else {
+            std::cerr << "Unimplemented.\n";
+            return 1;
+        }
+    } catch (po::required_option &ignored) {
         return 1;
-    }
-
-    int day;
-    int_from_cstr(day, argv[1]);
-
-    const aoc2019::solution_t solution = aoc2019::get_implementation(day);
-    if (solution != nullptr) {
-        solution(std::cin, std::cout);
-        return 0;
-    } else {
-        std::cerr << "Unimplemented.\n";
+    } catch (std::out_of_range &ignored) {
+        std::cerr << "Invalid day.\n";
         return 1;
     }
 }

From 944e595b971a5dc412c989a0d1f8898ef795a631 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 12:06:12 +0200
Subject: [PATCH 03/25] Wrong output variable.

---
 2019/src/day01.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2019/src/day01.cpp b/2019/src/day01.cpp
index af57e58..250339f 100644
--- a/2019/src/day01.cpp
+++ b/2019/src/day01.cpp
@@ -25,7 +25,7 @@ void aoc2019::day01_part2(std::istream &input, std::ostream &output) {
         for (auto drift : drifts) {
             cur += drift;
             if (seen.count(cur) == 1) {
-                output << drift << std::endl;
+                output << cur << std::endl;
                 return;
             } else {
                 seen.insert(cur);

From 5cead82bee3c85b180784f9fd95cf487b90da26a Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 12:08:46 +0200
Subject: [PATCH 04/25] Add timing code.

---
 2019/src/runner.cpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/2019/src/runner.cpp b/2019/src/runner.cpp
index e07fb05..7cf8004 100644
--- a/2019/src/runner.cpp
+++ b/2019/src/runner.cpp
@@ -1,4 +1,5 @@
 #include "solutions.hpp"
+#include <chrono>
 #include <iostream>
 #include <boost/program_options.hpp>
 
@@ -7,14 +8,16 @@ namespace po = boost::program_options;
 struct AoCOptions {
     int day;
     bool part2;
+    bool run_timer;
 };
 
-AoCOptions parse_options(const int argc, const char* argv[]) {
+static AoCOptions parse_options(const int argc, const char *argv[]) {
     AoCOptions options{};
     po::options_description desc("Allowed options");
     desc.add_options()
             ("day", po::value<int>(&options.day)->required(), "The day to run.")
-            ("part2,2", po::bool_switch(&options.part2), "Whether to run part 2.");
+            ("part2,2", po::bool_switch(&options.part2), "Whether to run part 2.")
+            ("timer,t", po::bool_switch(&options.run_timer), "Show the execution time.");
 
     po::positional_options_description positionals;
     positionals.add("day", 1);
@@ -33,7 +36,12 @@ int main(int argc, const char *argv[]) {
 
         const aoc2019::solution_t solution = aoc2019::get_implementation(options.day, options.part2);
         if (solution != nullptr) {
+            const auto start = std::chrono::high_resolution_clock::now();
             solution(std::cin, std::cout);
+            if (options.run_timer) {
+                const std::chrono::duration<double> duration = std::chrono::high_resolution_clock::now() - start;
+                std::cerr << "Time taken: " << duration.count() << "s\n";
+            }
             return 0;
         } else {
             std::cerr << "Unimplemented.\n";

From 54c704a8219021217f8775f301cc7cb83bf4abfa Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 12:18:47 +0200
Subject: [PATCH 05/25] Cleaner runner.

---
 2019/src/runner.cpp | 56 ++++++++++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 26 deletions(-)

diff --git a/2019/src/runner.cpp b/2019/src/runner.cpp
index 7cf8004..5beefcb 100644
--- a/2019/src/runner.cpp
+++ b/2019/src/runner.cpp
@@ -6,51 +6,55 @@
 namespace po = boost::program_options;
 
 struct AoCOptions {
-    int day;
-    bool part2;
+    aoc2019::solution_t implementation;
     bool run_timer;
 };
 
 static AoCOptions parse_options(const int argc, const char *argv[]) {
     AoCOptions options{};
+    int day;
+    bool part2;
     po::options_description desc("Allowed options");
     desc.add_options()
-            ("day", po::value<int>(&options.day)->required(), "The day to run.")
-            ("part2,2", po::bool_switch(&options.part2), "Whether to run part 2.")
+            ("day", po::value<int>(&day)->required(), "The day to run.")
+            ("part2,2", po::bool_switch(&part2), "Whether to run part 2.")
             ("timer,t", po::bool_switch(&options.run_timer), "Show the execution time.");
 
     po::positional_options_description positionals;
     positionals.add("day", 1);
 
-    po::variables_map vm;
+    try {
+        po::variables_map vm;
 
-    po::store(po::command_line_parser(argc, argv).options(desc).positional(positionals).run(), vm);
-    po::notify(vm);
+        po::store(po::command_line_parser(argc, argv).options(desc).positional(positionals).run(), vm);
+        po::notify(vm);
 
-    return options;
+        options.implementation = aoc2019::get_implementation(day, part2);
+
+        return options;
+    } catch (po::error &argument_error) {
+        std::cerr << argument_error.what() << std::endl;
+        std::exit(1);
+    } catch (std::out_of_range &) {
+        std::cerr << "Invalid day: " << day
+                  << ".\n Valid range: [1, 25].\n";
+        std::exit(1);
+    }
 }
 
 int main(int argc, const char *argv[]) {
-    try {
-        const auto options = parse_options(argc, argv);
+    const auto options = parse_options(argc, argv);
 
-        const aoc2019::solution_t solution = aoc2019::get_implementation(options.day, options.part2);
-        if (solution != nullptr) {
-            const auto start = std::chrono::high_resolution_clock::now();
-            solution(std::cin, std::cout);
-            if (options.run_timer) {
-                const std::chrono::duration<double> duration = std::chrono::high_resolution_clock::now() - start;
-                std::cerr << "Time taken: " << duration.count() << "s\n";
-            }
-            return 0;
-        } else {
-            std::cerr << "Unimplemented.\n";
-            return 1;
+    if (options.implementation != nullptr) {
+        const auto start = std::chrono::high_resolution_clock::now();
+        options.implementation(std::cin, std::cout);
+        if (options.run_timer) {
+            const std::chrono::duration<double> duration = std::chrono::high_resolution_clock::now() - start;
+            std::cerr << "Time taken: " << duration.count() << "s\n";
         }
-    } catch (po::required_option &ignored) {
-        return 1;
-    } catch (std::out_of_range &ignored) {
-        std::cerr << "Invalid day.\n";
+        return 0;
+    } else {
+        std::cerr << "Unimplemented.\n";
         return 1;
     }
 }

From a7587240c69bb8f91ffa5536db646777d854832d Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 12:30:46 +0200
Subject: [PATCH 06/25] Update travis script for 2019.

---
 .travis.yml | 29 ++++++++++-------------------
 1 file changed, 10 insertions(+), 19 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index f585909..48e8efd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,24 +1,15 @@
-language: rust
-rust:
-    - stable
-    - beta
-    - nightly
-    - 1.28.0 # Ubuntu Bionic and Xenial
+language: cpp
+dist: bionic
+compiler:
+    - clang
+    - gcc
 
-matrix:
-    allow_failures:
-        - rust: nightly
-        - rust: 1.28.0
-    fast_finish: true
-
-cache: cargo
 
 # Custom directory, for the correct year
 before_script:
-    - cd 2018
+    - cd 2019
 
-# After success on stable, run benchmark
-after_success:
-    - if [ "$TRAVIS_RUST_VERSION" == "stable" ]; then
-          cargo bench;
-      fi
+# CMake build
+script:
+    - cmake .
+    - make

From 11dd04ac828dd056416de1a912f7e43047233711 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 12:33:26 +0200
Subject: [PATCH 07/25] Relax CMake requirement.

---
 2019/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index f09fe54..7492ad1 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.15)
+cmake_minimum_required(VERSION 3.12)
 
 project(aoc2019)
 

From 5585bce297dc268ef08afa5549a85af3d9399477 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 12:38:17 +0200
Subject: [PATCH 08/25] Add boost to build.

---
 .travis.yml | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 48e8efd..275187d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,9 @@ before_script:
     - cd 2019
 
 # CMake build
-script:
-    - cmake .
-    - make
+script: cmake . && make
+
+addons:
+    apt:
+        packages:
+            - libboost-program-options-dev

From e26c90d54ad438424f317f5c7093c3500cf56f16 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 13:36:46 +0200
Subject: [PATCH 09/25] Add initial test set-up.

---
 .travis.yml                   |  1 +
 2019/CMakeLists.txt           | 10 +++++++++-
 2019/tests/test_solutions.cpp | 24 ++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 2019/tests/test_solutions.cpp

diff --git a/.travis.yml b/.travis.yml
index 275187d..1d6629a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,3 +16,4 @@ addons:
     apt:
         packages:
             - libboost-program-options-dev
+            - libboost-test-dev
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 7492ad1..90a4179 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.12)
 
 project(aoc2019)
 
-find_package(Boost REQUIRED COMPONENTS program_options)
+find_package(Boost REQUIRED COMPONENTS program_options unit_test_framework)
 
 add_library(AoCSolutions src/solutions.hpp src/solutions.cpp src/day01.cpp)
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
@@ -10,3 +10,11 @@ target_compile_features(AoCSolutions PUBLIC cxx_std_17)
 add_executable(runner src/runner.cpp)
 target_compile_features(runner PUBLIC cxx_std_17)
 target_link_libraries(runner AoCSolutions Boost::program_options)
+
+add_executable(test_solutions tests/test_solutions.cpp)
+target_compile_features(test_solutions PUBLIC cxx_std_17)
+target_link_libraries(test_solutions AoCSolutions Boost::unit_test_framework)
+target_include_directories(test_solutions PRIVATE ${CMAKE_SOURCE_DIR}/src)
+
+enable_testing()
+add_test(test_solutions test_solutions)
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
new file mode 100644
index 0000000..c0ddf7a
--- /dev/null
+++ b/2019/tests/test_solutions.cpp
@@ -0,0 +1,24 @@
+#define BOOST_TEST_MODULE solutions_tests
+
+#include <string>
+#include <boost/test/included/unit_test.hpp>
+#include "solutions.hpp"
+
+static std::string run_day1_part1(std::string_view input) {
+    std::stringstream input_stream;
+    input_stream.write(input.data(), input.size());
+
+    std::stringstream output_stream;
+
+    aoc2019::day01_part1(input_stream, output_stream);
+    return output_stream.str();
+}
+
+BOOST_AUTO_TEST_CASE(sample_day1_part1)
+{
+    BOOST_TEST(run_day1_part1("+1\n-2\n+3\n+1") == "3\n");
+    BOOST_TEST(run_day1_part1("+1\n+1\n+1") == "3\n");
+    BOOST_TEST(run_day1_part1("+1\n+1\n-2") == "0\n");
+}
+
+

From 4e5b3b5a15ab89464913ae31cb5b946403ffb2da Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 14:51:17 +0200
Subject: [PATCH 10/25] Implement generic testing for 2019.

This method reads a specific directory and applies all inputs there to
their proper implementation.
---
 .travis.yml                   |  2 +-
 2019/CMakeLists.txt           |  6 ++--
 2019/tests/samples/01-1-1.in  |  4 +++
 2019/tests/samples/01-1-1.out |  1 +
 2019/tests/samples/01-1-2.in  |  3 ++
 2019/tests/samples/01-1-2.out |  1 +
 2019/tests/samples/01-1-3.in  |  3 ++
 2019/tests/samples/01-1-3.out |  1 +
 2019/tests/samples/01-1-4.in  |  3 ++
 2019/tests/samples/01-1-4.out |  1 +
 2019/tests/test_solutions.cpp | 53 +++++++++++++++++++++++++++--------
 11 files changed, 63 insertions(+), 15 deletions(-)
 create mode 100644 2019/tests/samples/01-1-1.in
 create mode 100644 2019/tests/samples/01-1-1.out
 create mode 100644 2019/tests/samples/01-1-2.in
 create mode 100644 2019/tests/samples/01-1-2.out
 create mode 100644 2019/tests/samples/01-1-3.in
 create mode 100644 2019/tests/samples/01-1-3.out
 create mode 100644 2019/tests/samples/01-1-4.in
 create mode 100644 2019/tests/samples/01-1-4.out

diff --git a/.travis.yml b/.travis.yml
index 1d6629a..99b9dda 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,7 +10,7 @@ before_script:
     - cd 2019
 
 # CMake build
-script: cmake . && make
+script: cmake . && make && ./test_solutions
 
 addons:
     apt:
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 90a4179..2c30c6f 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -14,7 +14,9 @@ target_link_libraries(runner AoCSolutions Boost::program_options)
 add_executable(test_solutions tests/test_solutions.cpp)
 target_compile_features(test_solutions PUBLIC cxx_std_17)
 target_link_libraries(test_solutions AoCSolutions Boost::unit_test_framework)
-target_include_directories(test_solutions PRIVATE ${CMAKE_SOURCE_DIR}/src)
+target_include_directories(test_solutions PRIVATE "${CMAKE_SOURCE_DIR}/src")
 
 enable_testing()
-add_test(test_solutions test_solutions)
+add_test(NAME test_solutions
+         COMMAND test_solutions
+         WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/tests")
diff --git a/2019/tests/samples/01-1-1.in b/2019/tests/samples/01-1-1.in
new file mode 100644
index 0000000..9205ed4
--- /dev/null
+++ b/2019/tests/samples/01-1-1.in
@@ -0,0 +1,4 @@
++1
+-2
++3
++1
diff --git a/2019/tests/samples/01-1-1.out b/2019/tests/samples/01-1-1.out
new file mode 100644
index 0000000..00750ed
--- /dev/null
+++ b/2019/tests/samples/01-1-1.out
@@ -0,0 +1 @@
+3
diff --git a/2019/tests/samples/01-1-2.in b/2019/tests/samples/01-1-2.in
new file mode 100644
index 0000000..5d703f6
--- /dev/null
+++ b/2019/tests/samples/01-1-2.in
@@ -0,0 +1,3 @@
++1
++1
++1
diff --git a/2019/tests/samples/01-1-2.out b/2019/tests/samples/01-1-2.out
new file mode 100644
index 0000000..00750ed
--- /dev/null
+++ b/2019/tests/samples/01-1-2.out
@@ -0,0 +1 @@
+3
diff --git a/2019/tests/samples/01-1-3.in b/2019/tests/samples/01-1-3.in
new file mode 100644
index 0000000..399f99d
--- /dev/null
+++ b/2019/tests/samples/01-1-3.in
@@ -0,0 +1,3 @@
++1
++1
+-2
diff --git a/2019/tests/samples/01-1-3.out b/2019/tests/samples/01-1-3.out
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/2019/tests/samples/01-1-3.out
@@ -0,0 +1 @@
+0
diff --git a/2019/tests/samples/01-1-4.in b/2019/tests/samples/01-1-4.in
new file mode 100644
index 0000000..5be202d
--- /dev/null
+++ b/2019/tests/samples/01-1-4.in
@@ -0,0 +1,3 @@
+-1
+-2
+-3
diff --git a/2019/tests/samples/01-1-4.out b/2019/tests/samples/01-1-4.out
new file mode 100644
index 0000000..3cfb5ef
--- /dev/null
+++ b/2019/tests/samples/01-1-4.out
@@ -0,0 +1 @@
+-6
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index c0ddf7a..464e10b 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -1,24 +1,53 @@
 #define BOOST_TEST_MODULE solutions_tests
 
+#include <filesystem>
+#include <regex>
 #include <string>
+#include <tuple>
 #include <boost/test/included/unit_test.hpp>
+#include <boost/test/data/test_case.hpp>
 #include "solutions.hpp"
 
-static std::string run_day1_part1(std::string_view input) {
-    std::stringstream input_stream;
-    input_stream.write(input.data(), input.size());
+std::vector<std::string> get_samples() {
+    std::vector<std::string> samples;
+    for (auto entry : std::filesystem::directory_iterator("./samples")) {
+        if (entry.path().filename().extension() == ".in") {
+            samples.push_back(entry.path().string());
+        }
+    }
 
-    std::stringstream output_stream;
-
-    aoc2019::day01_part1(input_stream, output_stream);
-    return output_stream.str();
+    return samples;
 }
 
-BOOST_AUTO_TEST_CASE(sample_day1_part1)
-{
-    BOOST_TEST(run_day1_part1("+1\n-2\n+3\n+1") == "3\n");
-    BOOST_TEST(run_day1_part1("+1\n+1\n+1") == "3\n");
-    BOOST_TEST(run_day1_part1("+1\n+1\n-2") == "0\n");
+static std::string read_file(const std::string &file_name) {
+    std::ifstream file(file_name);
+    return std::string(std::istreambuf_iterator<char>(file),
+                       std::istreambuf_iterator<char>());
 }
 
+static void test_solution_impl(const std::string &input_name) {
+    std::regex name_parser("/(\\d{2})-(1|2).*\\.in$");
+    std::smatch match;
+    // Sanity check, is this a parseable input file?
+    BOOST_TEST(std::regex_search(input_name, match, name_parser));
 
+    const auto output_filename = input_name.substr(0, input_name.length() - 3) + ".out";
+    const int day = std::atoi(match[1].str().c_str());
+    const int part2 = match[2].str() == "2";
+
+    const auto desired_output = read_file(output_filename);
+    const auto implementation = aoc2019::get_implementation(day, part2);
+
+    std::stringstream output_buffer;
+    std::ifstream input(input_name);
+
+    implementation(input, output_buffer);
+
+    BOOST_TEST(desired_output == output_buffer.str());
+}
+
+BOOST_DATA_TEST_CASE(test_solution,
+                     boost::unit_test::data::make(get_samples()),
+                     input_name) {
+    test_solution_impl(input_name);
+}

From ab91276fca437bf76d87b8d08a1672971d1c53cd Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 12 Sep 2019 14:59:24 +0200
Subject: [PATCH 11/25] Replace std::filesystem with boost::filesystem.

Somehow, travis still doesn't support the right one.
---
 .travis.yml                   | 3 ++-
 2019/CMakeLists.txt           | 4 ++--
 2019/tests/test_solutions.cpp | 5 ++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 99b9dda..cd0dd7a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,10 +10,11 @@ before_script:
     - cd 2019
 
 # CMake build
-script: cmake . && make && ./test_solutions
+script: cmake . && make && make test
 
 addons:
     apt:
         packages:
+            - libboost-filesystem-dev
             - libboost-program-options-dev
             - libboost-test-dev
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 2c30c6f..d8c7ad6 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.12)
 
 project(aoc2019)
 
-find_package(Boost REQUIRED COMPONENTS program_options unit_test_framework)
+find_package(Boost REQUIRED COMPONENTS program_options unit_test_framework filesystem)
 
 add_library(AoCSolutions src/solutions.hpp src/solutions.cpp src/day01.cpp)
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
@@ -13,7 +13,7 @@ target_link_libraries(runner AoCSolutions Boost::program_options)
 
 add_executable(test_solutions tests/test_solutions.cpp)
 target_compile_features(test_solutions PUBLIC cxx_std_17)
-target_link_libraries(test_solutions AoCSolutions Boost::unit_test_framework)
+target_link_libraries(test_solutions AoCSolutions Boost::unit_test_framework Boost::filesystem)
 target_include_directories(test_solutions PRIVATE "${CMAKE_SOURCE_DIR}/src")
 
 enable_testing()
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 464e10b..81e24fa 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -1,16 +1,15 @@
 #define BOOST_TEST_MODULE solutions_tests
 
-#include <filesystem>
 #include <regex>
 #include <string>
-#include <tuple>
+#include <boost/filesystem.hpp>
 #include <boost/test/included/unit_test.hpp>
 #include <boost/test/data/test_case.hpp>
 #include "solutions.hpp"
 
 std::vector<std::string> get_samples() {
     std::vector<std::string> samples;
-    for (auto entry : std::filesystem::directory_iterator("./samples")) {
+    for (const auto &entry : boost::filesystem::directory_iterator("./samples")) {
         if (entry.path().filename().extension() == ".in") {
             samples.push_back(entry.path().string());
         }

From 4f1ddec0027e024035ea039ec51ea888ddbba7e2 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 15 Sep 2019 13:12:00 +0200
Subject: [PATCH 12/25] Ensure the test order is consistent.

---
 2019/tests/test_solutions.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 81e24fa..454043a 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -15,6 +15,9 @@ std::vector<std::string> get_samples() {
         }
     }
 
+    // Ensure a consistent order.
+    std::sort(samples.begin(), samples.end());
+
     return samples;
 }
 

From c046d5da01d85e5ec4757c05a42d0337ae49d0cd Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 15 Sep 2019 13:44:26 +0200
Subject: [PATCH 13/25] Restructure header files.

This should prevent the tests from being recompiled.
---
 2019/CMakeLists.txt                             | 2 +-
 2019/src/day01.cpp                              | 2 +-
 2019/src/{solutions.hpp => days.hpp}            | 4 ----
 2019/src/{solutions.cpp => implementations.cpp} | 3 ++-
 2019/src/implementations.hpp                    | 9 +++++++++
 2019/src/runner.cpp                             | 2 +-
 2019/tests/test_solutions.cpp                   | 2 +-
 7 files changed, 15 insertions(+), 9 deletions(-)
 rename 2019/src/{solutions.hpp => days.hpp} (63%)
 rename 2019/src/{solutions.cpp => implementations.cpp} (84%)
 create mode 100644 2019/src/implementations.hpp

diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index d8c7ad6..7e17420 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -4,7 +4,7 @@ project(aoc2019)
 
 find_package(Boost REQUIRED COMPONENTS program_options unit_test_framework filesystem)
 
-add_library(AoCSolutions src/solutions.hpp src/solutions.cpp src/day01.cpp)
+add_library(AoCSolutions src/implementations.hpp src/implementations.cpp src/day01.cpp src/days.hpp)
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
 
 add_executable(runner src/runner.cpp)
diff --git a/2019/src/day01.cpp b/2019/src/day01.cpp
index 250339f..a51511b 100644
--- a/2019/src/day01.cpp
+++ b/2019/src/day01.cpp
@@ -2,7 +2,7 @@
 #include <iterator>
 #include <vector>
 #include <unordered_set>
-#include "solutions.hpp"
+#include "days.hpp"
 
 // Currently an implementation of 2018 day 1
 void aoc2019::day01_part1(std::istream &input, std::ostream &output) {
diff --git a/2019/src/solutions.hpp b/2019/src/days.hpp
similarity index 63%
rename from 2019/src/solutions.hpp
rename to 2019/src/days.hpp
index 7ac9747..f511242 100644
--- a/2019/src/solutions.hpp
+++ b/2019/src/days.hpp
@@ -3,10 +3,6 @@
 #include <iosfwd>
 
 namespace aoc2019 {
-    typedef void (*solution_t)(std::istream &, std::ostream &);
-
-    solution_t get_implementation(int day, bool part2 = false);
-
     // Declarations of all implemented days.
     void day01_part1(std::istream &input, std::ostream &output);
     void day01_part2(std::istream &input, std::ostream &output);
diff --git a/2019/src/solutions.cpp b/2019/src/implementations.cpp
similarity index 84%
rename from 2019/src/solutions.cpp
rename to 2019/src/implementations.cpp
index bb8fd0d..570aca2 100644
--- a/2019/src/solutions.cpp
+++ b/2019/src/implementations.cpp
@@ -1,5 +1,6 @@
 #include <array>
-#include "solutions.hpp"
+#include "days.hpp"
+#include "implementations.hpp"
 
 constexpr const std::array<std::array<aoc2019::solution_t, 2>, 25> SOLUTIONS = {
         {aoc2019::day01_part1, aoc2019::day01_part2}
diff --git a/2019/src/implementations.hpp b/2019/src/implementations.hpp
new file mode 100644
index 0000000..24e9820
--- /dev/null
+++ b/2019/src/implementations.hpp
@@ -0,0 +1,9 @@
+#pragma once
+
+#include <iosfwd>
+
+namespace aoc2019 {
+    typedef void (*solution_t)(std::istream &, std::ostream &);
+
+    solution_t get_implementation(int day, bool part2 = false);
+}
diff --git a/2019/src/runner.cpp b/2019/src/runner.cpp
index 5beefcb..d47951c 100644
--- a/2019/src/runner.cpp
+++ b/2019/src/runner.cpp
@@ -1,4 +1,4 @@
-#include "solutions.hpp"
+#include "implementations.hpp"
 #include <chrono>
 #include <iostream>
 #include <boost/program_options.hpp>
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 454043a..370412d 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -5,7 +5,7 @@
 #include <boost/filesystem.hpp>
 #include <boost/test/included/unit_test.hpp>
 #include <boost/test/data/test_case.hpp>
-#include "solutions.hpp"
+#include "implementations.hpp"
 
 std::vector<std::string> get_samples() {
     std::vector<std::string> samples;

From 02066bf54a586a3af12a036f0f63e409ebbfdbb1 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 15 Sep 2019 15:46:34 +0200
Subject: [PATCH 14/25] Add README and update general one.

---
 2019/README.md | 6 ++++++
 README.md      | 1 +
 2 files changed, 7 insertions(+)
 create mode 100644 2019/README.md

diff --git a/2019/README.md b/2019/README.md
new file mode 100644
index 0000000..c8bb59a
--- /dev/null
+++ b/2019/README.md
@@ -0,0 +1,6 @@
+# Advent of Code 2019
+
+This project contains my implementations for Advent of Code 2019. The
+goal is to create reasonably fast C++ implementations in readable and
+ergonomic C++. At the end of the contest, I will probably do a write-
+up of some sorts. 
diff --git a/README.md b/README.md
index 01b3570..f469c8c 100644
--- a/README.md
+++ b/README.md
@@ -8,3 +8,4 @@ This repository contains my solutions for Advent of Code. See:
 - [2016 edition](./2016)
 - [2017 edition](./2017)
 - [2018 edition](./2018)
+- [2019 edition](./2019)

From 1f8e19c49b70340dc216b453fa7f162a5d9ca05e Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 17:13:31 +0200
Subject: [PATCH 15/25] Move to GTest for better integration.

---
 .travis.yml                   |  2 +-
 2019/CMakeLists.txt           | 11 ++--
 2019/tests/test_solutions.cpp | 98 ++++++++++++++++++++++-------------
 3 files changed, 68 insertions(+), 43 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index cd0dd7a..643a033 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,4 +17,4 @@ addons:
         packages:
             - libboost-filesystem-dev
             - libboost-program-options-dev
-            - libboost-test-dev
+            - libgtest-dev
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 7e17420..e58e7e4 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -2,7 +2,8 @@ cmake_minimum_required(VERSION 3.12)
 
 project(aoc2019)
 
-find_package(Boost REQUIRED COMPONENTS program_options unit_test_framework filesystem)
+find_package(Boost REQUIRED COMPONENTS program_options filesystem)
+find_package(GTest)
 
 add_library(AoCSolutions src/implementations.hpp src/implementations.cpp src/day01.cpp src/days.hpp)
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
@@ -13,10 +14,10 @@ target_link_libraries(runner AoCSolutions Boost::program_options)
 
 add_executable(test_solutions tests/test_solutions.cpp)
 target_compile_features(test_solutions PUBLIC cxx_std_17)
-target_link_libraries(test_solutions AoCSolutions Boost::unit_test_framework Boost::filesystem)
+target_link_libraries(test_solutions AoCSolutions Boost::filesystem gtest gtest_main)
+target_compile_definitions(test_solutions PRIVATE "TEST_SAMPLES_DIR=\"${CMAKE_SOURCE_DIR}/tests/samples\"")
 target_include_directories(test_solutions PRIVATE "${CMAKE_SOURCE_DIR}/src")
 
 enable_testing()
-add_test(NAME test_solutions
-         COMMAND test_solutions
-         WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/tests")
+include(GoogleTest)
+gtest_discover_tests(test_solutions)
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 370412d..399ff3c 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -1,15 +1,69 @@
 #define BOOST_TEST_MODULE solutions_tests
 
-#include <regex>
+#include <cassert>
+#include <cstdio>
 #include <string>
 #include <boost/filesystem.hpp>
-#include <boost/test/included/unit_test.hpp>
-#include <boost/test/data/test_case.hpp>
+#include <gtest/gtest.h>
 #include "implementations.hpp"
 
-std::vector<std::string> get_samples() {
+class SolutionsTest : public testing::TestWithParam<std::string> {
+protected:
+    std::string input_data = "";
+    std::string output_data = "";
+    aoc2019::solution_t implementation = nullptr;
+
+    // Read input data
+    void SetUp() override;
+
+private:
+    static void readToString(const std::string &name, std::string &target);
+};
+
+void SolutionsTest::SetUp() {
+    const auto input_name = GetParam();
+    const auto output_name = input_name.substr(0, input_name.length() - 3) + ".out";
+
+    const char *base_name = input_name.c_str();
+    if (const auto last_slash = input_name.rfind('/'); last_slash != std::string::npos) {
+        base_name += last_slash + 1;
+    }
+
+    int day, part;
+    const auto read_result = std::sscanf(base_name, "%02d-%1d-", &day, &part); // NOLINT(cert-err34-c)
+    // Ensure that we've read the input files.
+    assert(read_result != 0);
+
+    const bool part2 = part == 2;
+    implementation = aoc2019::get_implementation(day, part2);
+
+    readToString(input_name, input_data);
+    readToString(output_name, output_data);
+}
+
+void SolutionsTest::readToString(const std::string &name, std::string &target) {
+    std::ifstream source(name);
+
+    target.assign(std::istreambuf_iterator<char>(source),
+                  std::istreambuf_iterator<char>());
+}
+
+TEST_P(SolutionsTest, TestExpectedOutcome) {
+    std::stringstream input_buffer, output_buffer;
+
+    // Sanity check, don't call null implementation
+    ASSERT_NE(implementation, nullptr);
+
+    input_buffer.str(input_data);
+
+    implementation(input_buffer, output_buffer);
+
+    ASSERT_EQ(output_data, output_buffer.str());
+}
+
+static std::vector<std::string> get_samples() {
     std::vector<std::string> samples;
-    for (const auto &entry : boost::filesystem::directory_iterator("./samples")) {
+    for (const auto &entry : boost::filesystem::directory_iterator(TEST_SAMPLES_DIR)) {
         if (entry.path().filename().extension() == ".in") {
             samples.push_back(entry.path().string());
         }
@@ -21,35 +75,5 @@ std::vector<std::string> get_samples() {
     return samples;
 }
 
-static std::string read_file(const std::string &file_name) {
-    std::ifstream file(file_name);
-    return std::string(std::istreambuf_iterator<char>(file),
-                       std::istreambuf_iterator<char>());
-}
-
-static void test_solution_impl(const std::string &input_name) {
-    std::regex name_parser("/(\\d{2})-(1|2).*\\.in$");
-    std::smatch match;
-    // Sanity check, is this a parseable input file?
-    BOOST_TEST(std::regex_search(input_name, match, name_parser));
-
-    const auto output_filename = input_name.substr(0, input_name.length() - 3) + ".out";
-    const int day = std::atoi(match[1].str().c_str());
-    const int part2 = match[2].str() == "2";
-
-    const auto desired_output = read_file(output_filename);
-    const auto implementation = aoc2019::get_implementation(day, part2);
-
-    std::stringstream output_buffer;
-    std::ifstream input(input_name);
-
-    implementation(input, output_buffer);
-
-    BOOST_TEST(desired_output == output_buffer.str());
-}
-
-BOOST_DATA_TEST_CASE(test_solution,
-                     boost::unit_test::data::make(get_samples()),
-                     input_name) {
-    test_solution_impl(input_name);
-}
+INSTANTIATE_TEST_CASE_P(InstantiatedSolutionsTest, SolutionsTest,
+                        testing::ValuesIn(get_samples()));

From 7219712be423a59f92bbd2ff6bd80a1f8a1f19dc Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 17:30:09 +0200
Subject: [PATCH 16/25] Improve GTest configuration.

---
 2019/CMakeLists.txt | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index e58e7e4..6edf706 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -3,7 +3,7 @@ cmake_minimum_required(VERSION 3.12)
 project(aoc2019)
 
 find_package(Boost REQUIRED COMPONENTS program_options filesystem)
-find_package(GTest)
+find_package(GTest REQUIRED)
 
 add_library(AoCSolutions src/implementations.hpp src/implementations.cpp src/day01.cpp src/days.hpp)
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
@@ -12,12 +12,11 @@ add_executable(runner src/runner.cpp)
 target_compile_features(runner PUBLIC cxx_std_17)
 target_link_libraries(runner AoCSolutions Boost::program_options)
 
-add_executable(test_solutions tests/test_solutions.cpp)
-target_compile_features(test_solutions PUBLIC cxx_std_17)
-target_link_libraries(test_solutions AoCSolutions Boost::filesystem gtest gtest_main)
-target_compile_definitions(test_solutions PRIVATE "TEST_SAMPLES_DIR=\"${CMAKE_SOURCE_DIR}/tests/samples\"")
-target_include_directories(test_solutions PRIVATE "${CMAKE_SOURCE_DIR}/src")
+add_executable(unit_tests tests/test_solutions.cpp)
+target_compile_features(unit_tests PUBLIC cxx_std_17)
+target_link_libraries(unit_tests AoCSolutions Boost::filesystem GTest::GTest GTest::Main)
+target_compile_definitions(unit_tests PRIVATE "TEST_SAMPLES_DIR=\"${CMAKE_SOURCE_DIR}/tests/samples\"")
+target_include_directories(unit_tests PRIVATE "${CMAKE_SOURCE_DIR}/src")
 
 enable_testing()
-include(GoogleTest)
-gtest_discover_tests(test_solutions)
+gtest_discover_tests(unit_tests)

From c1dd06e65399a332f8ba09566e5d4fce4ddcd721 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 17:52:12 +0200
Subject: [PATCH 17/25] Build my own gtest.

Since the bundled version doesn't have a shared library.
---
 .travis.yml | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/.travis.yml b/.travis.yml
index 643a033..1be8373 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,19 @@
 language: cpp
 dist: bionic
+sudo: true
 compiler:
     - clang
     - gcc
 
 
+# Install GTest properly since it is only available as a static library.
+install:
+    - mkdir gtest_build
+    - pushd gtest_build
+    - cmake /usr/src/gtest -DBUILD_SHARED_LIBS=true
+    - make && sudo make install
+    - popd
+
 # Custom directory, for the correct year
 before_script:
     - cd 2019
@@ -18,3 +27,7 @@ addons:
             - libboost-filesystem-dev
             - libboost-program-options-dev
             - libgtest-dev
+
+cache:
+    directories:
+        - /home/travis/gtest_build

From 99c1522122a2f37ff1cb2c2780a487ccea0561e6 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 18:00:22 +0200
Subject: [PATCH 18/25] Don't soil build directory.

---
 .travis.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 1be8373..30b1e30 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,8 +8,8 @@ compiler:
 
 # Install GTest properly since it is only available as a static library.
 install:
-    - mkdir gtest_build
-    - pushd gtest_build
+    - mkdir ~/gtest_build
+    - pushd ~/gtest_build
     - cmake /usr/src/gtest -DBUILD_SHARED_LIBS=true
     - make && sudo make install
     - popd

From c7a7a98a39fd715cb6b924c23a76487d7f18a043 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 18:46:00 +0200
Subject: [PATCH 19/25] Rework test case names.

---
 2019/README.md                |  2 ++
 2019/tests/test_solutions.cpp | 59 ++++++++++++++++++++++++++---------
 2 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/2019/README.md b/2019/README.md
index c8bb59a..dc723dd 100644
--- a/2019/README.md
+++ b/2019/README.md
@@ -1,5 +1,7 @@
 # Advent of Code 2019
 
+[![Build Status](https://travis-ci.org/bertptrs/adventofcode.svg?branch=master)](https://travis-ci.org/bertptrs/adventofcode)
+
 This project contains my implementations for Advent of Code 2019. The
 goal is to create reasonably fast C++ implementations in readable and
 ergonomic C++. At the end of the contest, I will probably do a write-
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 399ff3c..6a9cd6b 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -1,13 +1,17 @@
 #define BOOST_TEST_MODULE solutions_tests
 
 #include <cassert>
-#include <cstdio>
+#include <cctype>
+#include <charconv>
 #include <string>
 #include <boost/filesystem.hpp>
 #include <gtest/gtest.h>
 #include "implementations.hpp"
 
 class SolutionsTest : public testing::TestWithParam<std::string> {
+public:
+    static std::string nameInstantiatedTest(const testing::TestParamInfo<SolutionsTest::ParamType> &paramInfo);
+
 protected:
     std::string input_data = "";
     std::string output_data = "";
@@ -18,23 +22,17 @@ protected:
 
 private:
     static void readToString(const std::string &name, std::string &target);
+
+    static std::tuple<int, bool, std::string> parseInputName(const std::string &name);
 };
 
 void SolutionsTest::SetUp() {
     const auto input_name = GetParam();
     const auto output_name = input_name.substr(0, input_name.length() - 3) + ".out";
 
-    const char *base_name = input_name.c_str();
-    if (const auto last_slash = input_name.rfind('/'); last_slash != std::string::npos) {
-        base_name += last_slash + 1;
-    }
-
-    int day, part;
-    const auto read_result = std::sscanf(base_name, "%02d-%1d-", &day, &part); // NOLINT(cert-err34-c)
-    // Ensure that we've read the input files.
-    assert(read_result != 0);
-
-    const bool part2 = part == 2;
+    int day;
+    bool part2;
+    std::tie(day, part2, std::ignore) = parseInputName(input_name);
     implementation = aoc2019::get_implementation(day, part2);
 
     readToString(input_name, input_data);
@@ -48,6 +46,38 @@ void SolutionsTest::readToString(const std::string &name, std::string &target) {
                   std::istreambuf_iterator<char>());
 }
 
+std::tuple<int, bool, std::string> SolutionsTest::parseInputName(const std::string &name) {
+    const char *base_name = name.c_str();
+    if (const auto last_slash = name.rfind('/'); last_slash != std::string::npos) {
+        base_name += last_slash + 1;
+    }
+    int day, part;
+    auto res = std::from_chars(base_name, base_name + 2, day);
+    assert(res.ec == std::errc());
+    res = std::from_chars(base_name + 3, base_name + 4, part);
+    assert(res.ec == std::errc());
+
+    return {day, part == 2, std::string(base_name + 5, std::strchr(base_name, '.'))};
+}
+
+std::string SolutionsTest::nameInstantiatedTest(const testing::TestParamInfo<SolutionsTest::ParamType> &paramInfo) {
+    int day;
+    bool part2;
+    std::string sampleName;
+
+    std::tie(day, part2, sampleName) = parseInputName(paramInfo.param);
+
+    std::stringstream nameBuilder;
+
+    nameBuilder << "Day" << day << "Part" << (part2 ? 2 : 1) << "Sample";
+
+    std::copy_if(sampleName.cbegin(), sampleName.cend(), std::ostream_iterator<char>(nameBuilder), [](char c) {
+        return std::isalnum(c);
+    });
+
+    return nameBuilder.str();
+}
+
 TEST_P(SolutionsTest, TestExpectedOutcome) {
     std::stringstream input_buffer, output_buffer;
 
@@ -75,5 +105,6 @@ static std::vector<std::string> get_samples() {
     return samples;
 }
 
-INSTANTIATE_TEST_CASE_P(InstantiatedSolutionsTest, SolutionsTest,
-                        testing::ValuesIn(get_samples()));
+INSTANTIATE_TEST_CASE_P(DaysTest, SolutionsTest,
+                        testing::ValuesIn(get_samples()),
+                        SolutionsTest::nameInstantiatedTest);

From 0130fedb61c409ce5b8dae61651653a5b5f28b9d Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 18:48:43 +0200
Subject: [PATCH 20/25] Recreate gtest dir only if necessary.

---
 .travis.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 30b1e30..993a085 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ compiler:
 
 # Install GTest properly since it is only available as a static library.
 install:
-    - mkdir ~/gtest_build
+    - mkdir -p ~/gtest_build
     - pushd ~/gtest_build
     - cmake /usr/src/gtest -DBUILD_SHARED_LIBS=true
     - make && sudo make install

From 4ba6fe48d1730c243423f80a7916fe8b8ee85071 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 19:06:03 +0200
Subject: [PATCH 21/25] Use recent GCC and Clang versions.

---
 .travis.yml | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 993a085..71dbe1d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,27 @@
 language: cpp
 dist: bionic
 sudo: true
-compiler:
-    - clang
-    - gcc
 
+matrix:
+    include:
+        - addons:
+            apt:
+                sources:
+                    - ubuntu-toolchain-r-test
+                    - llvm-toolchain-bionic-8
+                packages:
+                    - clang-8
+                    - libc++-8-dev
+                    - libc++abi-8-dev
+                    - libboost-filesystem-dev
+                    - libboost-program-options-dev
+                    - libgtest-dev
+          env:
+            - MATRIX_EVAL="CC=clang-8 && CXX=clang++-8"
+
+
+before_install:
+    - eval "$MATRIX_EVAL"
 
 # Install GTest properly since it is only available as a static library.
 install:
@@ -20,14 +37,3 @@ before_script:
 
 # CMake build
 script: cmake . && make && make test
-
-addons:
-    apt:
-        packages:
-            - libboost-filesystem-dev
-            - libboost-program-options-dev
-            - libgtest-dev
-
-cache:
-    directories:
-        - /home/travis/gtest_build

From 90b067ce0d9aaf5a2bb7bb56505ba163522a334d Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sun, 22 Sep 2019 19:43:42 +0200
Subject: [PATCH 22/25] Scratch running in travis.

Modern C++ is too difficult to run in travis/
---
 .travis.yml                   | 39 -----------------------------------
 2019/CMakeLists.txt           |  6 +++---
 2019/README.md                | 28 +++++++++++++++++++++++--
 2019/tests/test_solutions.cpp |  6 ++++--
 4 files changed, 33 insertions(+), 46 deletions(-)
 delete mode 100644 .travis.yml

diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 71dbe1d..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,39 +0,0 @@
-language: cpp
-dist: bionic
-sudo: true
-
-matrix:
-    include:
-        - addons:
-            apt:
-                sources:
-                    - ubuntu-toolchain-r-test
-                    - llvm-toolchain-bionic-8
-                packages:
-                    - clang-8
-                    - libc++-8-dev
-                    - libc++abi-8-dev
-                    - libboost-filesystem-dev
-                    - libboost-program-options-dev
-                    - libgtest-dev
-          env:
-            - MATRIX_EVAL="CC=clang-8 && CXX=clang++-8"
-
-
-before_install:
-    - eval "$MATRIX_EVAL"
-
-# Install GTest properly since it is only available as a static library.
-install:
-    - mkdir -p ~/gtest_build
-    - pushd ~/gtest_build
-    - cmake /usr/src/gtest -DBUILD_SHARED_LIBS=true
-    - make && sudo make install
-    - popd
-
-# Custom directory, for the correct year
-before_script:
-    - cd 2019
-
-# CMake build
-script: cmake . && make && make test
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 6edf706..5dea4ae 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.12)
 
 project(aoc2019)
 
-find_package(Boost REQUIRED COMPONENTS program_options filesystem)
+find_package(Boost REQUIRED COMPONENTS program_options)
 find_package(GTest REQUIRED)
 
 add_library(AoCSolutions src/implementations.hpp src/implementations.cpp src/day01.cpp src/days.hpp)
@@ -14,9 +14,9 @@ target_link_libraries(runner AoCSolutions Boost::program_options)
 
 add_executable(unit_tests tests/test_solutions.cpp)
 target_compile_features(unit_tests PUBLIC cxx_std_17)
-target_link_libraries(unit_tests AoCSolutions Boost::filesystem GTest::GTest GTest::Main)
+target_link_libraries(unit_tests AoCSolutions GTest::GTest GTest::Main)
 target_compile_definitions(unit_tests PRIVATE "TEST_SAMPLES_DIR=\"${CMAKE_SOURCE_DIR}/tests/samples\"")
 target_include_directories(unit_tests PRIVATE "${CMAKE_SOURCE_DIR}/src")
 
 enable_testing()
-gtest_discover_tests(unit_tests)
+gtest_discover_tests(unit_tests NO_PRETTY_VALUES)
diff --git a/2019/README.md b/2019/README.md
index dc723dd..160afe3 100644
--- a/2019/README.md
+++ b/2019/README.md
@@ -1,8 +1,32 @@
 # Advent of Code 2019
 
-[![Build Status](https://travis-ci.org/bertptrs/adventofcode.svg?branch=master)](https://travis-ci.org/bertptrs/adventofcode)
-
 This project contains my implementations for Advent of Code 2019. The
 goal is to create reasonably fast C++ implementations in readable and
 ergonomic C++. At the end of the contest, I will probably do a write-
 up of some sorts. 
+
+
+## How to compile
+
+Install the dependencies:
+
+- [GTest](https://github.com/google/googletest) **Note:** this project
+  by default tries to dynamically link GTest, and the Ubuntu packages
+  only provide a statically linked archive. You may need to compile it
+  for yourself.
+- [Boost.Program_options](https://www.boost.org/doc/libs/1_71_0/doc/html/program_options.html)
+
+```
+mkdir build && cd build
+cmake ..
+make
+```
+
+You can then use the generated executable `runner`.
+
+## Running tests
+
+Tests can be executed with `make test`. The `tests` folder contains a
+`samples` folder. This folder contains pairs of `XX-Y-something.in` and
+`XX-Y-something.out`, which will be taken as the expected input and
+output of the implementations. You can add your own samples to this mix.
diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 6a9cd6b..620c003 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -2,9 +2,11 @@
 
 #include <cassert>
 #include <cctype>
+#include <cstring>
 #include <charconv>
+#include <filesystem>
+#include <fstream>
 #include <string>
-#include <boost/filesystem.hpp>
 #include <gtest/gtest.h>
 #include "implementations.hpp"
 
@@ -93,7 +95,7 @@ TEST_P(SolutionsTest, TestExpectedOutcome) {
 
 static std::vector<std::string> get_samples() {
     std::vector<std::string> samples;
-    for (const auto &entry : boost::filesystem::directory_iterator(TEST_SAMPLES_DIR)) {
+    for (const auto &entry : std::filesystem::directory_iterator(TEST_SAMPLES_DIR)) {
         if (entry.path().filename().extension() == ".in") {
             samples.push_back(entry.path().string());
         }

From 5b91fd4da3b3a7eafa76159741e67deb6c1c39c9 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Wed, 25 Sep 2019 12:56:57 +0200
Subject: [PATCH 23/25] No longer depend on Boost.program_options.

---
 2019/CMakeLists.txt |  3 +-
 2019/README.md      |  1 -
 2019/src/runner.cpp | 99 +++++++++++++++++++++++++++++++++------------
 3 files changed, 74 insertions(+), 29 deletions(-)

diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 5dea4ae..a679e78 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -2,7 +2,6 @@ cmake_minimum_required(VERSION 3.12)
 
 project(aoc2019)
 
-find_package(Boost REQUIRED COMPONENTS program_options)
 find_package(GTest REQUIRED)
 
 add_library(AoCSolutions src/implementations.hpp src/implementations.cpp src/day01.cpp src/days.hpp)
@@ -10,7 +9,7 @@ target_compile_features(AoCSolutions PUBLIC cxx_std_17)
 
 add_executable(runner src/runner.cpp)
 target_compile_features(runner PUBLIC cxx_std_17)
-target_link_libraries(runner AoCSolutions Boost::program_options)
+target_link_libraries(runner AoCSolutions)
 
 add_executable(unit_tests tests/test_solutions.cpp)
 target_compile_features(unit_tests PUBLIC cxx_std_17)
diff --git a/2019/README.md b/2019/README.md
index 160afe3..f857611 100644
--- a/2019/README.md
+++ b/2019/README.md
@@ -14,7 +14,6 @@ Install the dependencies:
   by default tries to dynamically link GTest, and the Ubuntu packages
   only provide a statically linked archive. You may need to compile it
   for yourself.
-- [Boost.Program_options](https://www.boost.org/doc/libs/1_71_0/doc/html/program_options.html)
 
 ```
 mkdir build && cd build
diff --git a/2019/src/runner.cpp b/2019/src/runner.cpp
index d47951c..c3f6b5a 100644
--- a/2019/src/runner.cpp
+++ b/2019/src/runner.cpp
@@ -1,45 +1,92 @@
 #include "implementations.hpp"
+#include <charconv>
 #include <chrono>
 #include <iostream>
-#include <boost/program_options.hpp>
-
-namespace po = boost::program_options;
 
 struct AoCOptions {
     aoc2019::solution_t implementation;
     bool run_timer;
 };
 
-static AoCOptions parse_options(const int argc, const char *argv[]) {
+static AoCOptions parse_options(const int argc, const char* argv[]) {
+    using namespace std::string_view_literals;
     AoCOptions options{};
-    int day;
-    bool part2;
-    po::options_description desc("Allowed options");
-    desc.add_options()
-            ("day", po::value<int>(&day)->required(), "The day to run.")
-            ("part2,2", po::bool_switch(&part2), "Whether to run part 2.")
-            ("timer,t", po::bool_switch(&options.run_timer), "Show the execution time.");
 
-    po::positional_options_description positionals;
-    positionals.add("day", 1);
+    auto show_help = [argv] (int exit_status = 0) {
+        std::cerr << "Usage: " << argv[0] << " [--timer|-t] [--part2|-2] [--help|-h] DAY\n"
+                  << "\t--timer|-t: print execution time\n"
+                  << "\t--part2|-2: run part 2\n"
+                  << "\t --help|-h: show this message\n";
+        std::exit(exit_status);
+    };
 
-    try {
-        po::variables_map vm;
+    int day = -1;
+    bool part2 = false;
 
-        po::store(po::command_line_parser(argc, argv).options(desc).positional(positionals).run(), vm);
-        po::notify(vm);
+    // Here follows a manual implementation of getopt, since getopt doesn't work on windows…
+    for (int i = 1; i < argc; ++i) {
+        std::string_view arg(argv[i]);
+        if (arg[0] == '-') {
+            // Handle flag arguments
+            if (arg[1] != '-') {
+                // Shorthand flags
+                for (char c : arg.substr(1)) {
+                    switch (c) {
+                        case '2':
+                            part2 = true;
+                            break;
 
-        options.implementation = aoc2019::get_implementation(day, part2);
+                        case 't':
+                            options.run_timer = true;
+                            break;
 
-        return options;
-    } catch (po::error &argument_error) {
-        std::cerr << argument_error.what() << std::endl;
-        std::exit(1);
-    } catch (std::out_of_range &) {
-        std::cerr << "Invalid day: " << day
-                  << ".\n Valid range: [1, 25].\n";
-        std::exit(1);
+                        case 'h':
+                            show_help();
+                            break;
+
+                        default:
+                            std::cerr << "Unknown flag '" << c << "'.\n\n";
+                            show_help(1);
+                    }
+                }
+            } else {
+                // Handle long form versions
+                if (arg == "--timer"sv) {
+                    part2 = true;
+                } else if (arg == "--timer"sv) {
+                    options.run_timer = true;
+                } else if (arg == "--help"sv) {
+                    show_help();
+                } else {
+                    show_help(1);
+                }
+            }
+        } else {
+            if (day != -1) {
+                // Double date specification, bail.
+                show_help(1);
+            }
+
+            // Try to parse the date number
+            if (auto res = std::from_chars(arg.data(), arg.data() + arg.size(), day); res.ec != std::errc()) {
+                auto error_code = std::make_error_code(res.ec);
+                std::cerr << error_code.message() << "\n\n";
+                show_help(1);
+            }
+        }
     }
+
+    if (day == -1) {
+        std::cerr << "Argument DAY is required.\n\n";
+        show_help(1);
+    } else if (day < 1 || day > 25) {
+        std::cerr << "Invalid day. Valid range: [1, 25]\n";
+        show_help(1);
+    }
+
+    options.implementation = aoc2019::get_implementation(day, part2);
+
+    return options;
 }
 
 int main(int argc, const char *argv[]) {

From e9bf399af40524a5e0614f52b901745165d9b229 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 28 Nov 2019 08:00:46 +0100
Subject: [PATCH 24/25] Prepare all days skeletons.

---
 2019/CMakeLists.txt           |  3 ++-
 2019/src/day01.cpp            | 31 +++-------------------
 2019/src/day02.cpp            | 10 ++++++++
 2019/src/day03.cpp            | 10 ++++++++
 2019/src/day04.cpp            | 10 ++++++++
 2019/src/day05.cpp            | 10 ++++++++
 2019/src/day06.cpp            | 10 ++++++++
 2019/src/day07.cpp            | 10 ++++++++
 2019/src/day08.cpp            | 10 ++++++++
 2019/src/day09.cpp            | 10 ++++++++
 2019/src/day10.cpp            | 10 ++++++++
 2019/src/day11.cpp            | 10 ++++++++
 2019/src/day12.cpp            | 10 ++++++++
 2019/src/day13.cpp            | 10 ++++++++
 2019/src/day14.cpp            | 10 ++++++++
 2019/src/day15.cpp            | 10 ++++++++
 2019/src/day16.cpp            | 10 ++++++++
 2019/src/day17.cpp            | 10 ++++++++
 2019/src/day18.cpp            | 10 ++++++++
 2019/src/day19.cpp            | 10 ++++++++
 2019/src/day20.cpp            | 10 ++++++++
 2019/src/day21.cpp            | 10 ++++++++
 2019/src/day22.cpp            | 10 ++++++++
 2019/src/day23.cpp            | 10 ++++++++
 2019/src/day24.cpp            | 10 ++++++++
 2019/src/day25.cpp            | 10 ++++++++
 2019/src/days.hpp             | 48 +++++++++++++++++++++++++++++++++++
 2019/src/implementations.cpp  | 30 +++++++++++++++++++---
 2019/tests/samples/.gitkeep   |  1 +
 2019/tests/samples/01-1-1.in  |  4 ---
 2019/tests/samples/01-1-1.out |  1 -
 2019/tests/samples/01-1-2.in  |  3 ---
 2019/tests/samples/01-1-2.out |  1 -
 2019/tests/samples/01-1-3.in  |  3 ---
 2019/tests/samples/01-1-3.out |  1 -
 2019/tests/samples/01-1-4.in  |  3 ---
 2019/tests/samples/01-1-4.out |  1 -
 37 files changed, 321 insertions(+), 49 deletions(-)
 create mode 100644 2019/src/day02.cpp
 create mode 100644 2019/src/day03.cpp
 create mode 100644 2019/src/day04.cpp
 create mode 100644 2019/src/day05.cpp
 create mode 100644 2019/src/day06.cpp
 create mode 100644 2019/src/day07.cpp
 create mode 100644 2019/src/day08.cpp
 create mode 100644 2019/src/day09.cpp
 create mode 100644 2019/src/day10.cpp
 create mode 100644 2019/src/day11.cpp
 create mode 100644 2019/src/day12.cpp
 create mode 100644 2019/src/day13.cpp
 create mode 100644 2019/src/day14.cpp
 create mode 100644 2019/src/day15.cpp
 create mode 100644 2019/src/day16.cpp
 create mode 100644 2019/src/day17.cpp
 create mode 100644 2019/src/day18.cpp
 create mode 100644 2019/src/day19.cpp
 create mode 100644 2019/src/day20.cpp
 create mode 100644 2019/src/day21.cpp
 create mode 100644 2019/src/day22.cpp
 create mode 100644 2019/src/day23.cpp
 create mode 100644 2019/src/day24.cpp
 create mode 100644 2019/src/day25.cpp
 create mode 100644 2019/tests/samples/.gitkeep
 delete mode 100644 2019/tests/samples/01-1-1.in
 delete mode 100644 2019/tests/samples/01-1-1.out
 delete mode 100644 2019/tests/samples/01-1-2.in
 delete mode 100644 2019/tests/samples/01-1-2.out
 delete mode 100644 2019/tests/samples/01-1-3.in
 delete mode 100644 2019/tests/samples/01-1-3.out
 delete mode 100644 2019/tests/samples/01-1-4.in
 delete mode 100644 2019/tests/samples/01-1-4.out

diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index a679e78..1ee4f27 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -4,7 +4,8 @@ project(aoc2019)
 
 find_package(GTest REQUIRED)
 
-add_library(AoCSolutions src/implementations.hpp src/implementations.cpp src/day01.cpp src/days.hpp)
+file(GLOB DAYS_FILES src/day*.cpp)
+add_library(AoCSolutions src/implementations.cpp "${DAYS_FILES}")
 target_compile_features(AoCSolutions PUBLIC cxx_std_17)
 
 add_executable(runner src/runner.cpp)
diff --git a/2019/src/day01.cpp b/2019/src/day01.cpp
index a51511b..c4ff5e4 100644
--- a/2019/src/day01.cpp
+++ b/2019/src/day01.cpp
@@ -1,35 +1,10 @@
-#include <numeric>
-#include <iterator>
-#include <vector>
-#include <unordered_set>
+#include <iostream>
 #include "days.hpp"
 
-// Currently an implementation of 2018 day 1
 void aoc2019::day01_part1(std::istream &input, std::ostream &output) {
-    int sum = std::accumulate(std::istream_iterator<int>(input),
-                              std::istream_iterator<int>(),
-                              0);
-
-    output << sum << std::endl;
+	output << "Not implemented\n";
 }
 
 void aoc2019::day01_part2(std::istream &input, std::ostream &output) {
-    std::vector<int> drifts;
-    std::copy(std::istream_iterator<int>(input),
-              std::istream_iterator<int>(),
-              std::back_inserter(drifts));
-
-    int cur = 0;
-    std::unordered_set<int> seen{cur};
-    while (true) {
-        for (auto drift : drifts) {
-            cur += drift;
-            if (seen.count(cur) == 1) {
-                output << cur << std::endl;
-                return;
-            } else {
-                seen.insert(cur);
-            }
-        }
-    }
+	output << "Not implemented\n";
 }
diff --git a/2019/src/day02.cpp b/2019/src/day02.cpp
new file mode 100644
index 0000000..5bb6abf
--- /dev/null
+++ b/2019/src/day02.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day02_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day02_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day03.cpp b/2019/src/day03.cpp
new file mode 100644
index 0000000..dfc74de
--- /dev/null
+++ b/2019/src/day03.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day03_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day03_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day04.cpp b/2019/src/day04.cpp
new file mode 100644
index 0000000..c9f113f
--- /dev/null
+++ b/2019/src/day04.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day04_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day04_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day05.cpp b/2019/src/day05.cpp
new file mode 100644
index 0000000..af62105
--- /dev/null
+++ b/2019/src/day05.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day05_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day05_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day06.cpp b/2019/src/day06.cpp
new file mode 100644
index 0000000..52421fd
--- /dev/null
+++ b/2019/src/day06.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day06_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day06_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day07.cpp b/2019/src/day07.cpp
new file mode 100644
index 0000000..603b222
--- /dev/null
+++ b/2019/src/day07.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day07_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day07_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day08.cpp b/2019/src/day08.cpp
new file mode 100644
index 0000000..03855f3
--- /dev/null
+++ b/2019/src/day08.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day08_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day08_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day09.cpp b/2019/src/day09.cpp
new file mode 100644
index 0000000..28f8285
--- /dev/null
+++ b/2019/src/day09.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day09_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day09_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day10.cpp b/2019/src/day10.cpp
new file mode 100644
index 0000000..391e112
--- /dev/null
+++ b/2019/src/day10.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day10_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day10_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day11.cpp b/2019/src/day11.cpp
new file mode 100644
index 0000000..508ed43
--- /dev/null
+++ b/2019/src/day11.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day11_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day11_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day12.cpp b/2019/src/day12.cpp
new file mode 100644
index 0000000..16cb2a8
--- /dev/null
+++ b/2019/src/day12.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day12_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day12_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day13.cpp b/2019/src/day13.cpp
new file mode 100644
index 0000000..39dd64c
--- /dev/null
+++ b/2019/src/day13.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day13_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day13_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day14.cpp b/2019/src/day14.cpp
new file mode 100644
index 0000000..b0441a4
--- /dev/null
+++ b/2019/src/day14.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day14_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day14_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day15.cpp b/2019/src/day15.cpp
new file mode 100644
index 0000000..6fa383f
--- /dev/null
+++ b/2019/src/day15.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day15_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day15_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day16.cpp b/2019/src/day16.cpp
new file mode 100644
index 0000000..61765e5
--- /dev/null
+++ b/2019/src/day16.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day16_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day16_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day17.cpp b/2019/src/day17.cpp
new file mode 100644
index 0000000..a979207
--- /dev/null
+++ b/2019/src/day17.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day17_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day17_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day18.cpp b/2019/src/day18.cpp
new file mode 100644
index 0000000..4783ee1
--- /dev/null
+++ b/2019/src/day18.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day18_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day18_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day19.cpp b/2019/src/day19.cpp
new file mode 100644
index 0000000..aa2248c
--- /dev/null
+++ b/2019/src/day19.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day19_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day19_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day20.cpp b/2019/src/day20.cpp
new file mode 100644
index 0000000..bb8a3a7
--- /dev/null
+++ b/2019/src/day20.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day20_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day20_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day21.cpp b/2019/src/day21.cpp
new file mode 100644
index 0000000..89decc1
--- /dev/null
+++ b/2019/src/day21.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day21_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day21_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day22.cpp b/2019/src/day22.cpp
new file mode 100644
index 0000000..70e3852
--- /dev/null
+++ b/2019/src/day22.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day22_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day22_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day23.cpp b/2019/src/day23.cpp
new file mode 100644
index 0000000..383e9f5
--- /dev/null
+++ b/2019/src/day23.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day23_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day23_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day24.cpp b/2019/src/day24.cpp
new file mode 100644
index 0000000..632ed30
--- /dev/null
+++ b/2019/src/day24.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day24_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day24_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/day25.cpp b/2019/src/day25.cpp
new file mode 100644
index 0000000..0eb6ade
--- /dev/null
+++ b/2019/src/day25.cpp
@@ -0,0 +1,10 @@
+#include <iostream>
+#include "days.hpp"
+
+void aoc2019::day25_part1(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
+
+void aoc2019::day25_part2(std::istream &input, std::ostream &output) {
+	output << "Not implemented\n";
+}
diff --git a/2019/src/days.hpp b/2019/src/days.hpp
index f511242..f34ed64 100644
--- a/2019/src/days.hpp
+++ b/2019/src/days.hpp
@@ -6,4 +6,52 @@ namespace aoc2019 {
     // Declarations of all implemented days.
     void day01_part1(std::istream &input, std::ostream &output);
     void day01_part2(std::istream &input, std::ostream &output);
+    void day02_part1(std::istream &input, std::ostream &output);
+    void day02_part2(std::istream &input, std::ostream &output);
+    void day03_part1(std::istream &input, std::ostream &output);
+    void day03_part2(std::istream &input, std::ostream &output);
+    void day04_part1(std::istream &input, std::ostream &output);
+    void day04_part2(std::istream &input, std::ostream &output);
+    void day05_part1(std::istream &input, std::ostream &output);
+    void day05_part2(std::istream &input, std::ostream &output);
+    void day06_part1(std::istream &input, std::ostream &output);
+    void day06_part2(std::istream &input, std::ostream &output);
+    void day07_part1(std::istream &input, std::ostream &output);
+    void day07_part2(std::istream &input, std::ostream &output);
+    void day08_part1(std::istream &input, std::ostream &output);
+    void day08_part2(std::istream &input, std::ostream &output);
+    void day09_part1(std::istream &input, std::ostream &output);
+    void day09_part2(std::istream &input, std::ostream &output);
+    void day10_part1(std::istream &input, std::ostream &output);
+    void day10_part2(std::istream &input, std::ostream &output);
+    void day11_part1(std::istream &input, std::ostream &output);
+    void day11_part2(std::istream &input, std::ostream &output);
+    void day12_part1(std::istream &input, std::ostream &output);
+    void day12_part2(std::istream &input, std::ostream &output);
+    void day13_part1(std::istream &input, std::ostream &output);
+    void day13_part2(std::istream &input, std::ostream &output);
+    void day14_part1(std::istream &input, std::ostream &output);
+    void day14_part2(std::istream &input, std::ostream &output);
+    void day15_part1(std::istream &input, std::ostream &output);
+    void day15_part2(std::istream &input, std::ostream &output);
+    void day16_part1(std::istream &input, std::ostream &output);
+    void day16_part2(std::istream &input, std::ostream &output);
+    void day17_part1(std::istream &input, std::ostream &output);
+    void day17_part2(std::istream &input, std::ostream &output);
+    void day18_part1(std::istream &input, std::ostream &output);
+    void day18_part2(std::istream &input, std::ostream &output);
+    void day19_part1(std::istream &input, std::ostream &output);
+    void day19_part2(std::istream &input, std::ostream &output);
+    void day20_part1(std::istream &input, std::ostream &output);
+    void day20_part2(std::istream &input, std::ostream &output);
+    void day21_part1(std::istream &input, std::ostream &output);
+    void day21_part2(std::istream &input, std::ostream &output);
+    void day22_part1(std::istream &input, std::ostream &output);
+    void day22_part2(std::istream &input, std::ostream &output);
+    void day23_part1(std::istream &input, std::ostream &output);
+    void day23_part2(std::istream &input, std::ostream &output);
+    void day24_part1(std::istream &input, std::ostream &output);
+    void day24_part2(std::istream &input, std::ostream &output);
+    void day25_part1(std::istream &input, std::ostream &output);
+    void day25_part2(std::istream &input, std::ostream &output);
 }
diff --git a/2019/src/implementations.cpp b/2019/src/implementations.cpp
index 570aca2..9111331 100644
--- a/2019/src/implementations.cpp
+++ b/2019/src/implementations.cpp
@@ -2,9 +2,33 @@
 #include "days.hpp"
 #include "implementations.hpp"
 
-constexpr const std::array<std::array<aoc2019::solution_t, 2>, 25> SOLUTIONS = {
-        {aoc2019::day01_part1, aoc2019::day01_part2}
-};
+constexpr const std::array<std::array<aoc2019::solution_t, 2>, 25> SOLUTIONS = {{
+        {aoc2019::day01_part1, aoc2019::day01_part2},
+        {aoc2019::day02_part1, aoc2019::day02_part2},
+        {aoc2019::day03_part1, aoc2019::day03_part2},
+        {aoc2019::day04_part1, aoc2019::day04_part2},
+        {aoc2019::day05_part1, aoc2019::day05_part2},
+        {aoc2019::day06_part1, aoc2019::day06_part2},
+        {aoc2019::day07_part1, aoc2019::day07_part2},
+        {aoc2019::day08_part1, aoc2019::day08_part2},
+        {aoc2019::day09_part1, aoc2019::day09_part2},
+        {aoc2019::day10_part1, aoc2019::day10_part2},
+        {aoc2019::day11_part1, aoc2019::day11_part2},
+        {aoc2019::day12_part1, aoc2019::day12_part2},
+        {aoc2019::day13_part1, aoc2019::day13_part2},
+        {aoc2019::day14_part1, aoc2019::day14_part2},
+        {aoc2019::day15_part1, aoc2019::day15_part2},
+        {aoc2019::day16_part1, aoc2019::day16_part2},
+        {aoc2019::day17_part1, aoc2019::day17_part2},
+        {aoc2019::day18_part1, aoc2019::day18_part2},
+        {aoc2019::day19_part1, aoc2019::day19_part2},
+        {aoc2019::day20_part1, aoc2019::day20_part2},
+        {aoc2019::day21_part1, aoc2019::day21_part2},
+        {aoc2019::day22_part1, aoc2019::day22_part2},
+        {aoc2019::day23_part1, aoc2019::day23_part2},
+        {aoc2019::day24_part1, aoc2019::day24_part2},
+        {aoc2019::day25_part1, aoc2019::day25_part2},
+}};
 
 aoc2019::solution_t aoc2019::get_implementation(int day, bool part2) {
     return SOLUTIONS.at(day - 1).at((int) part2);
diff --git a/2019/tests/samples/.gitkeep b/2019/tests/samples/.gitkeep
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/2019/tests/samples/.gitkeep
@@ -0,0 +1 @@
+
diff --git a/2019/tests/samples/01-1-1.in b/2019/tests/samples/01-1-1.in
deleted file mode 100644
index 9205ed4..0000000
--- a/2019/tests/samples/01-1-1.in
+++ /dev/null
@@ -1,4 +0,0 @@
-+1
--2
-+3
-+1
diff --git a/2019/tests/samples/01-1-1.out b/2019/tests/samples/01-1-1.out
deleted file mode 100644
index 00750ed..0000000
--- a/2019/tests/samples/01-1-1.out
+++ /dev/null
@@ -1 +0,0 @@
-3
diff --git a/2019/tests/samples/01-1-2.in b/2019/tests/samples/01-1-2.in
deleted file mode 100644
index 5d703f6..0000000
--- a/2019/tests/samples/01-1-2.in
+++ /dev/null
@@ -1,3 +0,0 @@
-+1
-+1
-+1
diff --git a/2019/tests/samples/01-1-2.out b/2019/tests/samples/01-1-2.out
deleted file mode 100644
index 00750ed..0000000
--- a/2019/tests/samples/01-1-2.out
+++ /dev/null
@@ -1 +0,0 @@
-3
diff --git a/2019/tests/samples/01-1-3.in b/2019/tests/samples/01-1-3.in
deleted file mode 100644
index 399f99d..0000000
--- a/2019/tests/samples/01-1-3.in
+++ /dev/null
@@ -1,3 +0,0 @@
-+1
-+1
--2
diff --git a/2019/tests/samples/01-1-3.out b/2019/tests/samples/01-1-3.out
deleted file mode 100644
index 573541a..0000000
--- a/2019/tests/samples/01-1-3.out
+++ /dev/null
@@ -1 +0,0 @@
-0
diff --git a/2019/tests/samples/01-1-4.in b/2019/tests/samples/01-1-4.in
deleted file mode 100644
index 5be202d..0000000
--- a/2019/tests/samples/01-1-4.in
+++ /dev/null
@@ -1,3 +0,0 @@
--1
--2
--3
diff --git a/2019/tests/samples/01-1-4.out b/2019/tests/samples/01-1-4.out
deleted file mode 100644
index 3cfb5ef..0000000
--- a/2019/tests/samples/01-1-4.out
+++ /dev/null
@@ -1 +0,0 @@
--6

From c63b962cb31ec4c2577a9466eb3848db402ab9b7 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 28 Nov 2019 08:09:37 +0100
Subject: [PATCH 25/25] Fix Clang incompatibility.

std::strchar should return const pointer for const input but it doesn't.
---
 2019/tests/test_solutions.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/2019/tests/test_solutions.cpp b/2019/tests/test_solutions.cpp
index 620c003..ea870bc 100644
--- a/2019/tests/test_solutions.cpp
+++ b/2019/tests/test_solutions.cpp
@@ -1,5 +1,3 @@
-#define BOOST_TEST_MODULE solutions_tests
-
 #include <cassert>
 #include <cctype>
 #include <cstring>
@@ -59,7 +57,7 @@ std::tuple<int, bool, std::string> SolutionsTest::parseInputName(const std::stri
     res = std::from_chars(base_name + 3, base_name + 4, part);
     assert(res.ec == std::errc());
 
-    return {day, part == 2, std::string(base_name + 5, std::strchr(base_name, '.'))};
+    return {day, part == 2, std::string(base_name + 5, (const char*) std::strchr(base_name, '.'))};
 }
 
 std::string SolutionsTest::nameInstantiatedTest(const testing::TestParamInfo<SolutionsTest::ParamType> &paramInfo) {