Add project files.

Day1/Program.cs

@@ -0,0 +1,14 @@
+var lines = File.ReadAllLines("input.txt");
+
+var parts = lines.Select(line => (line.Split("   ")[0], line.Split("   ")[1])).ToList();
+var list1 = parts.Select(part => int.Parse(part.Item1)).Order().ToList();
+var list2 = parts.Select(part => int.Parse(part.Item2)).Order().ToList();
+int distance = 0, similarityScore = 0;
+
+for (var i = 0; i < list1.Count; i++)
+{
+    distance += Math.Abs(list1[i] - list2[i]);
+    similarityScore += list1[i] * list2.Count(item => item == list1[i]);
+}
+
+Console.WriteLine($"Part 1 : {distance}\nPart 2 : {similarityScore}");