added part 2 info

days/day01.cpp

@@ -109,5 +109,72 @@ void day01::Part1()
 	{
 		sum += std::abs(col1[i] - col2[i]);
 	}
-	std::cout << sum << '\n';
+}
+
+/*
+--- Part Two ---
+
+Your analysis only confirmed what everyone feared: the two lists of location IDs are indeed very different.
+
+Or are they?
+
+The Historians can't agree on which group made the mistakes or how to read most of the Chief's handwriting,
+but in the commotion you notice an interesting detail: a lot of location IDs appear in both lists! Maybe the other
+numbers aren't location IDs at all but rather misinterpreted handwriting.
+
+This time, you'll need to figure out exactly how often each number from the left list appears in the right
+list. Calculate a total similarity score by adding up each number in the left list after multiplying it by the number
+of times that number appears in the right list.
+
+Here are the same example lists again:
+
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3
+
+For these example lists, here is the process of finding the similarity score:
+
+	The first number in the left list is 3. It appears in the right list three times, so the similarity score increases by 3 * 3 = 9.
+	The second number in the left list is 4. It appears in the right list once, so the similarity score increases by 4 * 1 = 4.
+	The third number in the left list is 2. It does not appear in the right list, so the similarity score does not increase (2 * 0 = 0).
+	The fourth number, 1, also does not appear in the right list.
+	The fifth number, 3, appears in the right list three times; the similarity score increases by 9.
+	The last number, 3, appears in the right list three times; the similarity score again increases by 9.
+
+So, for these example lists, the similarity score at the end of this process is 31 (9 + 4 + 0 + 0 + 9 + 9).
+
+Once again consider your left and right lists. What is their similarity score?
+
+ */
+
+void day01::Part2()
+{
+	std::vector<int> col1;
+	std::vector<int> col2;
+	int sum = 0;
+
+	std::ifstream input("input/day01.txt");
+	//std::ifstream input("input/day01short.txt");
+
+	if (!input)
+	{
+		std::cerr << "Failed to open input file." << std::endl;
+		std::cout << "Current path is " << std::filesystem::current_path() << '\n';
+
+		return;
+	}
+
+	std::string delimiter = "   ";
+	auto delimiterLength = delimiter.length();
+
+	std::string line;
+	while (std::getline(input, line))
+	{
+		auto delimiterPos = line.find(delimiter);
+		col1.emplace_back(std::stoi(line.substr(0, delimiterPos)));
+		col2.emplace_back(std::stoi(line.substr(delimiterPos + delimiterLength, line.length())));
+	}
 }