Advent-of-Code/2023/1_old/main.cpp

#include <cctype>
#include <fstream>
#include <iostream>
#include <vector>

#define INPUT_FILE "input2.txt"

int ParseNumLine1(const std::string &line);
int ParseNumLine2(const std::string &line);

int main()
{
	std::ifstream ifs(INPUT_FILE);
	if(!ifs.is_open())
	{
		std::cerr << "Couldn't open " INPUT_FILE "." << std::endl;
		return -1;
	}

	long result1 = 0;
	long result2 = 0;
	for(std::string line = ""; std::getline(ifs, line); )
	{
		result1 += ParseNumLine1(line);
		result2 += ParseNumLine2(line);
	}

	std::cout << "Part 1 Result: " << result1 << std::endl;
	std::cout << "Part 2 Result: " << result2 << std::endl;

	return 0;
}

int ParseNumLine1(const std::string &line)
{
	char found[3] = { '\0', '\0', '\0' };
	bool found_first = false;
	for(auto &ch : line)
	{
		if(std::isdigit(ch))
		{
			if(!found_first)
			{
				found[0] = ch;
				found_first = true;
			}

			// same as first, if only one
			found[1] = ch;
		}
	}
	return std::atoi(found);
}

int ParseNumLine2(const std::string &line)
{
	char found[3] = { '\0', '\0', '\0' };
	bool found_first = false;
	for(auto &ch : line)
	{
		if(std::isdigit(ch))
		{
			if(!found_first)
			{
				found[0] = ch;
				found_first = true;
			}

			// same as first, if only one
			found[1] = ch;
		}
		else
		{
			const static std::vector<std::string> available = {
				"one",
				"two",
				"three",
				"four",
				"five",
				"six",
				"seven",
				"eight",
				"nine",
			};

			int num = 0;
			for(auto i = 0; i < line.size(); ++i)
			{
				for(auto w = 0; w < available.size(); ++w)
				{
					const std::string &word = available[w];
					if(line.size() - i < word.size())
						continue; // not enough letters for this word

					bool word_matches = true;
					for(auto letter = 0; i + letter < line.size() && word_matches; ++letter)
					{
						if(line[i + letter] != word[letter])
						{
							word_matches = false;
							break;
						}
						if(letter == word.size() - 1)
						{
							num = w + 1;
							// std::cout << "Found: ";
							// for(auto a = 0; a <= letter; ++a)
							// 	std::cout << line[i + a];
							// std::cout << " == " << available[w] << " @ " << letter << std::endl;
							break; // true!
						}
					}
					if(word_matches)
						break;
				}

				if(num)
				{
					if(!found_first)
					{
						found[0] = num + '0';
						found_first = true;
					}

					found[1] = num + '0';

					num = 0;
				}
			}
		}
	}
	std::cout << "Return: " << found << " == " << std::atoi(found) << std::endl;
	return std::atoi(found);
}