Add day 2

Day2/Program.cs

@@ -0,0 +1,41 @@
+var lines = File.ReadAllLines("input.txt");
+
+var reports = lines.Select(line => line.Split(" ").ToList()).ToList();
+
+int safeReportsNumber = 0, problemDampenerSafeReports = 0;
+
+for (int i = 0; i < reports.Count; i++)
+{
+    var currentReport = reports[i].Select(x => int.Parse(x)).ToList();
+
+    if (IsReportSafe(currentReport)) safeReportsNumber++;
+
+    if (IsReportSafeWithDampener(currentReport)) problemDampenerSafeReports++;
+}
+
+Console.WriteLine($"Part1: {safeReportsNumber}\nPart2: {problemDampenerSafeReports}");
+
+bool IsReportSafe(List<int> levels)
+{
+    var isAscending = levels.SequenceEqual(levels.OrderBy(x => x));
+    var isDescending = levels.SequenceEqual(levels.OrderByDescending(x => x));
+    var allValidDifferennce = levels.Zip(levels.Skip(1), (a, b) => Math.Abs(a - b) > 0 && Math.Abs(a - b) < 4).All(x => x);
+
+    return (isAscending || isDescending) && allValidDifferennce;
+}
+
+bool IsReportSafeWithDampener(List<int> levels)
+{
+    if (IsReportSafe(levels)) return true;
+
+    // Performance killa..
+    for (int i = 0; i < levels.Count; i++)
+    {
+        var modifiedLevels = new List<int>(levels);
+        modifiedLevels.RemoveAt(i);
+
+        if (IsReportSafe(modifiedLevels)) return true;
+    }
+
+    return false;
+}