first three days

day3/CMakeLists.txt

@@ -0,0 +1,29 @@
+cmake_minimum_required(VERSION 3.10)
+
+# Project name and version
+project(Day3 VERSION 1.0)
+
+# Set default build type
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE Debug)
+endif()
+
+# 1. This is the critical line for Clangd. 
+# It generates the file clangd reads to know where headers are.
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Debug and Release flags
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g -O0 -Wall -Wextra")
+set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3")
+
+# Specify C standard
+set(CMAKE_CXX_STANDARD 23)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Add include directory
+include_directories(${PROJECT_SOURCE_DIR}/include)
+
+# Add executable
+add_executable(${PROJECT_NAME} 
+    src/main.cpp
+)

day3/Makefile

@@ -0,0 +1,13 @@
+
+
+clear:
+	rm -rf build/*
+
+run:
+	cp input.txt build
+	cp input_test.txt build
+	cd build && cmake .. && make && ./Day3 input_test.txt
+
+release:
+	cp input.txt build
+	cd build && cmake .. -DCMAKE_BUILD_TYPE=Release && make && ./Day3 input.txt

day3/flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1756787288,
+        "narHash": "sha256-rw/PHa1cqiePdBxhF66V7R+WAP8WekQ0mCDG4CFqT8Y=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "d0fc30899600b9b3466ddb260fd83deb486c32f1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

day3/flake.nix

@@ -0,0 +1,58 @@
+{
+  description = "A Nix-flake-based C/C++ development environment";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  outputs =
+    { self, nixpkgs }:
+    let
+      supportedSystems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
+      forEachSupportedSystem =
+        f:
+        nixpkgs.lib.genAttrs supportedSystems (
+          system:
+          f {
+            pkgs = import nixpkgs { inherit system; };
+          }
+        );
+    in
+    {
+      devShells = forEachSupportedSystem (
+        { pkgs }:
+        {
+          default =
+            pkgs.mkShell.override
+              {
+                # Override stdenv in order to change compiler:
+                # stdenv = pkgs.clangStdenv;
+              }
+
+              {
+                nativeBuildInputs = with pkgs; [
+                  pkg-config
+                ];
+                packages =
+                  with pkgs;
+                  [
+                    clang-tools
+                    cmake
+                    codespell
+                    cppcheck
+                    doxygen
+                    gtest
+                    lcov
+                    nodejs
+                    vscode-extensions.vadimcn.vscode-lldb
+                  ]
+                  ++ (if system == "aarch64-darwin" then [ ] else [ gdb ]);
+                CODELLDB_PATH = "${pkgs.vscode-extensions.vadimcn.vscode-lldb}/share/vscode/extensions/vadimcn.vscode-lldb/adapter/codelldb";
+              };
+        }
+      );
+    };
+}

day3/input_test.txt

@@ -0,0 +1,4 @@
+987654321111111
+811111111111119
+234234234234278
+818181911112111

day3/src/main.cpp

@@ -0,0 +1,90 @@
+#include <cmath>
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <numeric>
+#include <vector>
+
+int do_part_1(const std::string &line) {
+  int greatest = -1;
+  int second_greatest = -1;
+  for (size_t i = 0; i < line.length(); i++) {
+    char c = line[i];
+    int j = static_cast<int>(c - '0');
+    if (j > greatest && i < (line.length() - 1)) {
+      second_greatest = -1;
+      greatest = j;
+    } else if (j > second_greatest) {
+      second_greatest = j;
+    }
+  }
+
+  auto joint = std::to_string(greatest) + std::to_string(second_greatest);
+
+  return std::stoi(joint);
+}
+
+int find_highest_leading(std::string &line, int len) {
+  int highest_leading = -1;
+  int highest_pos = -1;
+  for (size_t i = 0; i < (line.length() - len + 1); i++) {
+    int j = static_cast<int>(line[i] - '0');
+    if (j > highest_leading) {
+      highest_leading = j;
+      highest_pos = i;
+    }
+  }
+  line = line.substr(highest_pos + 1);
+  return highest_leading;
+}
+
+long do_part_2(std::string line) {
+  std::string highest_seq = "";
+  for (int i = 12; i > 0; i--) {
+    std::cout << "line " << line << std::endl;
+    int highest_leading = find_highest_leading(line, i);
+    highest_seq += std::to_string(highest_leading);
+  }
+  return std::stol(highest_seq);
+}
+
+std::tuple<long, long> parse_input_file(const std::string &path) {
+  std::ifstream file;
+  std::string line;
+
+  file.open(path);
+  long part_1 = 0;
+  long part_2 = 0;
+  std::vector<int> part1_ints;
+  std::vector<long> part2_longs;
+  if (file.is_open()) {
+    std::getline(file, line);
+    while (!line.empty()) {
+      part_1 = do_part_1(line);
+      part1_ints.emplace_back(part_1);
+      part_2 = do_part_2(line);
+      part2_longs.emplace_back(part_2);
+      std::getline(file, line);
+    }
+  } else {
+    std::cerr << "Error opening file: " << path << std::endl;
+    return {0, 0};
+  }
+
+  part_1 = std::accumulate(part1_ints.begin(), part1_ints.end(), 0L);
+  part_2 = std::accumulate(part2_longs.begin(), part2_longs.end(), 0L);
+
+  return {part_1, part_2};
+}
+
+int main(int argc, char *argv[]) {
+  if (argc < 2) {
+    std::cout << "One argument required: input txt" << std::endl;
+  }
+
+  auto results = parse_input_file(argv[1]);
+  std::cout << "Part 1: " << std::get<0>(results) << std::endl;
+  std::cout << "Part 2: " << std::get<1>(results) << std::endl;
+
+  return 0;
+}