Day2Part1

CMakeLists.txt

@@ -6,6 +6,33 @@ set(CMAKE_CXX_COMPILER /usr/bin/clang++-21)
 
 project(aoc25 VERSION 0.1.0 LANGUAGES C CXX)
 
+# Helper to add AoC day targets and auto-copy any input files
+function(aoc_add_day name src_dir)
+	# remaining args are source files
+	set(sources ${ARGN})
+
+	add_executable(${name} ${sources})
+	set_target_properties(${name} PROPERTIES CXX_STANDARD 23 CXX_STANDARD_REQUIRED ON)
+	# Use GCC toolchain compatibility for clang++-21
+	target_compile_options(${name} PRIVATE --gcc-toolchain=/usr)
+
+	# Gather common input files in the source directory
+	file(GLOB INPUT_FILES
+		"${src_dir}/*_input"
+		"${src_dir}/puzzle_input"
+		"${src_dir}/test_input"
+	)
+
+	foreach(f IN LISTS INPUT_FILES)
+		get_filename_component(fname ${f} NAME)
+		add_custom_command(TARGET ${name} POST_BUILD
+			COMMAND ${CMAKE_COMMAND} -E copy ${f} $<TARGET_FILE_DIR:${name}>/${fname}
+			COMMENT "Copying ${fname} to build directory for ${name}"
+		)
+	endforeach()
+endfunction()
+
 # Per-day subprojects (example: day1)
 add_subdirectory(day1)
+add_subdirectory(day2)
 

day1/CMakeLists.txt

@@ -1,11 +1,2 @@
-add_executable(day1 main.cpp)
-set_target_properties(day1 PROPERTIES CXX_STANDARD 23 CXX_STANDARD_REQUIRED ON)
-# Use GCC 15's libstdc++ with Clang 21
-target_compile_options(day1 PRIVATE --gcc-toolchain=/usr)
-
-add_custom_command(TARGET day1 POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy
-    ${CMAKE_CURRENT_SOURCE_DIR}/day1_input
-    $<TARGET_FILE_DIR:day1>/day1_input
-    COMMENT "Copying day1_input to build directory"
-)
+ # Use top-level helper to add the target and copy input files
+ aoc_add_day(day1 "${CMAKE_CURRENT_SOURCE_DIR}" main.cpp)

day1/main.cpp

@@ -67,10 +67,6 @@ auto executeSafeCrack(const std::vector<DialRotation>& dialRotations){
             }
         }
 
-       
-
-
-
         std::println("{} : {:3}, Dial now at: {:5} cnt: {}", curDial.direction, curDial.distance, dial, countZero); 
         if (dial < 0){
             std::cout << "Shit's fucked!\n";
@@ -86,7 +82,6 @@ auto executeSafeCrack(const std::vector<DialRotation>& dialRotations){
 }   
 
 auto main(int, char**) -> int {
-    std::cout << "Hello, from aoc25 day1!!\n";
     auto retval = parseRotations("day1_input");
 
     std::vector<DialRotation> testCase = {
@@ -103,8 +98,7 @@ auto main(int, char**) -> int {
         {'L', 1000},
     };
 
-    if(retval)
-    {
+    if(retval) {
         auto realResult = executeSafeCrack(*retval);
         auto result = executeSafeCrack(testCase);
         std::println("Testcase result: {}", result);

day2/CMakeLists.txt

@@ -0,0 +1,2 @@
+ # Use top-level helper to add the target and copy input files
+ aoc_add_day(day2 "${CMAKE_CURRENT_SOURCE_DIR}" main.cpp)

day2/main.cpp

@@ -0,0 +1,83 @@
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <expected>
+#include <print>
+#include <ranges>
+
+struct IDRange {
+    std::string leftRange;
+    std::string rightRange;
+};
+
+auto parseRanges(const std::string& filename) -> std::expected<std::vector<IDRange>, std::string> { 
+    std::ifstream inputF {filename};
+    
+    if (!inputF){
+        return std::unexpected{"Some file open error.\n"};
+    }
+    std::vector<IDRange> idRanges{}; 
+
+    std::string bigString{};
+    std::getline(inputF,bigString);
+    auto ranges = std::ranges::to<std::vector<std::string>>(std::views::split(bigString, ','));
+
+    for(const auto& range : ranges){
+        auto subParts = std::ranges::to<std::vector<std::string>>(std::views::split(range, '-'));
+        idRanges.emplace_back(subParts[0], subParts[1]);
+    }
+
+    inputF.close();
+
+    return std::move(idRanges);
+}
+
+
+
+auto countDoubles(const std::vector<IDRange>& idRanges) {
+    long doubles{};
+    for(const auto& rng : idRanges){
+        //std::println("{}-{}", rng.leftRange, rng.rightRange);
+        for( long i = std::stol(rng.leftRange); i <= std::stol(rng.rightRange); i++){
+            auto str_version = std::to_string(i) ;
+            auto str_len = str_version.size();
+            //std::print("Checking {}. Length: {}", str_version, str_version.size());
+            if (str_len % 2 == 0) {
+                //std::print(" Divisible by two, splitting...");
+                std::string_view left_half = std::string_view(str_version).substr(0, str_len/2);
+                std::string_view right_half = std::string_view(str_version).substr(str_len/2, str_len);
+                //std::print("Halves: {}/{}",left_half, right_half);
+                if(left_half == right_half){
+                    //std::print(" EQUAL!");
+                    doubles += i;
+                }
+            }
+            //std::println();
+        }
+    }
+    return doubles;
+}   
+
+auto main() -> int {
+    auto testCase = parseRanges("test_input");
+    if(testCase) {
+            auto testResult = countDoubles(*testCase);
+            std::println("Testcase result: {}", testResult);
+    }
+    else{
+        std::print("{}\n", testCase.error());    
+    }
+
+
+    auto realRanges = parseRanges("puzzle_input");
+    if(realRanges) {
+            auto realResult = countDoubles(*realRanges);
+            std::println("Real result: {}", realResult);
+    }
+    else{
+        std::print("{}\n", realRanges.error());    
+    }
+    
+    return 0;
+}

day2/puzzle_input

@@ -0,0 +1 @@
+9191906840-9191941337,7671-13230,2669677096-2669816099,2-12,229599-392092,48403409-48523311,96763-229430,1919163519-1919240770,74928-96389,638049-668065,34781-73835,736781-819688,831765539-831907263,5615884-5749554,14101091-14196519,7134383-7169141,413340-625418,849755289-849920418,7745350-7815119,16717-26267,4396832-4549887,87161544-87241541,4747436629-4747494891,335-549,867623-929630,53-77,1414-3089,940604-1043283,3444659-3500714,3629-7368,79-129,5488908-5597446,97922755-98097602,182-281,8336644992-8336729448,24-47,613-1077

day2/test_input

@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124