Added some missing old files and new day2 of 2024.

2023/1/Makefile

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+a.out: main.cpp
+	clang++ -g -std=c++20 main.cpp

2023/1/input2.txt

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+two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen

2023/1/main.cpp

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+#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);
+}

2023/1/sample.txt

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+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet