2016 day 7

AOC.Test/Test2016.cs

@@ -12,6 +12,7 @@ public class Test2016
     [DataRow(typeof(Day04), "361724", "482")]
     //[DataRow(typeof(Day05), "F77A0E6E", "999828EC")] // TODO: optimize
     [DataRow(typeof(Day06), "gyvwpxaz", "jucfoary")]
+    [DataRow(typeof(Day07), "105", "258")]
     public void CheckAllDays(Type dayType, string part1, string part2) =>
         Common.CheckDay(dayType, part1, part2);
 

AOC2016/Day07.cs

@@ -3,13 +3,62 @@ namespace AOC2016;
 /// <summary>
 /// Day 7: <a href="https://adventofcode.com/2016/day/7"/>
 /// </summary>
-public sealed class Day07() : Day(2016, 7, "Puzzle Name")
+public sealed partial class Day07() : Day(2016, 7, "Internet Protocol Version 7")
 {
+    [GeneratedRegex(@"\[[^\]]*\]")]
+    private static partial Regex BracketsRegex();
+
+    [GeneratedRegex(@"\[(\w*)\]")]
+    private static partial Regex InsideBracketsRegex();
+
+    private List<string> _input = null!;
+
     public override void ProcessInput()
     {
+        _input = Input.ToList();
     }
 
-    public override object Part1() => "";
+    private static bool SupportsTls(string input)
+    {
+        foreach (Match m in InsideBracketsRegex().Matches(input))
+        {
+            if (CheckAbba(m.ValueSpan)) return false;
+        }
 
-    public override object Part2() => "";
-}
+        return BracketsRegex().Split(input).Any(v => CheckAbba(v));
+    }
+
+    private static bool CheckAbba(ReadOnlySpan<char> input)
+    {
+        for (var i = 0; i < input.Length - 3; i++)
+        {
+            if (input[i] == input[i + 3] &&
+                input[i + 1] == input[i + 2] &&
+                input[i] != input[i + 1])
+                return true;
+        }
+
+        return false;
+    }
+
+    private static bool SupportsSsl(string input)
+    {
+        foreach (var ip in BracketsRegex().Split(input))
+        foreach (var aba in CheckAba(ip))
+        foreach (Match m in InsideBracketsRegex().Matches(input))
+            if (m.Value.Contains($"{aba[1]}{aba[0]}{aba[1]}"))
+                return true;
+
+        return false;
+    }
+
+    private static IEnumerable<string> CheckAba(string input)
+    {
+        for (var i = 0; i < input.Length - 2; i++)
+            if (input[i] == input[i + 2] && input[i] != input[i + 1])
+                yield return input.Substring(i, 3);
+    }
+
+    public override object Part1() => _input.Count(SupportsTls);
+    public override object Part2() => _input.Count(SupportsSsl);
+}