#include #include bool is_invalid_part_1(long int id) { std::string id_str = std::to_string(id); for (int i = 1; i < id_str.size(); i++) { if (id_str.substr(0, i) + id_str.substr(0, i) == id_str) { return true; } } return false; } bool is_invalid_part_2(long int id) { std::string id_str = std::to_string(id); for (int repeat_length = 1; repeat_length < id_str.size(); repeat_length++) { for (int repeat_count = 0; repeat_count < id_str.size() / repeat_length + 1; repeat_count++) { std::string new_str; for (int i = 0; i < repeat_count; i++) { new_str += id_str.substr(0, repeat_length); } if (new_str == id_str) return true; } } return false; } int main() { std::ifstream file("input.txt"); long int part_1_invalid_sum = 0, part_2_invalid_sum = 0; std::string range; while (getline(file, range, ',')) { long int range_start, range_end; sscanf(range.c_str(), "%ld-%ld", &range_start, &range_end); std::cout << "Range " << range_start << "-" << range_end << std::endl; for (long int i = range_start; i <= range_end; i++) { if (is_invalid_part_1(i)) part_1_invalid_sum += i; if (is_invalid_part_2(i)) part_2_invalid_sum += i; } } std::cout << std::endl; std::cout << "Sum of invalid IDs:\n Part 1: " << part_1_invalid_sum << "\n Part 2: " << part_2_invalid_sum << std::endl; }