2024-01,02

2024/Day02.cs

@@ -4,7 +4,21 @@ public class Day02 : ISolution
 {
     public void Run()
     {
-        var _ = File.ReadAllText("input/02");
-        Console.WriteLine("The solution for day 02 is not implmented yet");
+        var input = File.ReadAllText("input/02")
+            .Split('\n')
+            .Select(line => line.Split(' ')
+                .Select(int.Parse)
+                .ToList())
+            .ToList();
+
+        Console.WriteLine(PartOne(input));
+    }
+    
+    private static int PartOne(List<List<int>> list) {
+        return list.Select(line => Enumerable.Range(1, Math.Max(0, line.Count - 1))
+                .Select(i => line[i] - line[i - 1])
+                .ToList())
+            .Where(diffs => diffs.All(d => d > 0) || diffs.All(d => d < 0))
+            .Count(diffs => !diffs.Any(d => Math.Abs(d) is < 1 or > 3));
     }
 }