02

02/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.10)
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED True)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+enable_language(CXX)
+
+project(AoC02)
+
+if(APPLE)
+    include_directories(/usr/local/include)
+    link_directories(/usr/local/lib)
+endif()
+
+if(WIN32)
+	add_executable(${CMAKE_PROJECT_NAME} WIN32)
+else()
+	add_executable(${CMAKE_PROJECT_NAME})
+endif()
+
+target_sources(${CMAKE_PROJECT_NAME}
+	PRIVATE main.cpp
+	)

02/main.cpp

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+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+enum Command {
+    Forward,
+    Down,
+    Up,
+    Undefined,
+};
+using CommandPair = std::pair<Command, int>;
+
+std::vector<CommandPair> getCommands(const std::string &file_name) {
+    std::ifstream file(file_name);
+    std::vector<CommandPair> result{};
+    std::string tmp_command{};
+    int tmp_num{};
+    std::string str;
+    while (std::getline(file, str)) {
+        std::stringstream ss(str);
+        ss >> tmp_command;
+        ss >> tmp_num;
+        Command cmd = Undefined;
+        if (tmp_command == "forward") {
+            cmd = Forward;
+        } else if (tmp_command == "down") {
+            cmd = Down;
+        } else if (tmp_command == "up") {
+            cmd = Up;
+        }
+        if (cmd == Undefined) {
+            std::cerr << "Invalid input line: \"" << str << "\"" << std::endl;
+            return {};
+        }
+        result.emplace_back(cmd, tmp_num);
+    }
+    return result;
+}
+
+int part1(const std::vector<CommandPair> &commands) {
+    int x = 0;
+    int y = 0;
+    for (const auto &command : commands) {
+        switch (command.first) {
+        case Forward:
+            x += command.second;
+            break;
+        case Down:
+            y += command.second;
+            break;
+        case Up:
+            y -= command.second;
+        default:
+            break;
+        }
+    }
+    return x * y;
+}
+
+int part2(const std::vector<CommandPair> &commands) {
+    int x = 0;
+    int y = 0;
+    int aim = 0;
+    for (const auto &command : commands) {
+        switch (command.first) {
+        case Forward:
+            x += command.second;
+            y += aim * command.second;
+            break;
+        case Down:
+            aim += command.second;
+            break;
+        case Up:
+            aim -= command.second;
+        default:
+            break;
+        }
+    }
+    return x * y;
+}
+
+int main(int argc, char **argv) {
+    if (argc < 2) {
+        std::cerr << "You must provide input file!" << std::endl;
+        return 1;
+    }
+    auto commands = getCommands(argv[1]);
+    if (commands.empty()) {
+        return 1;
+    }
+    std::cout << "The resulting multiplication is \033[91;1m" << part1(commands)
+              << "\033[0m." << std::endl;
+    std::cout << "The correct resulting multiplication is \033[91;1m"
+              << part2(commands) << "\033[0m." << std::endl;
+    return 0;
+}