Add day 2

Day2/Day2.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Update="input.txt">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

Day2/Program.cs

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+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;
+}