Add day 11

AdventOfCode2024.sln

@@ -23,6 +23,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Day9", "Day9\Day9.csproj",
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Day10", "Day10\Day10.csproj", "{9DA97BBA-99AF-4FA7-97BB-C6EF3F8B24A4}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Day11", "Day11\Day11.csproj", "{FE187D99-D153-4909-959C-FA9C81444D11}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -69,6 +71,10 @@ Global
 		{9DA97BBA-99AF-4FA7-97BB-C6EF3F8B24A4}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{9DA97BBA-99AF-4FA7-97BB-C6EF3F8B24A4}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{9DA97BBA-99AF-4FA7-97BB-C6EF3F8B24A4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FE187D99-D153-4909-959C-FA9C81444D11}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FE187D99-D153-4909-959C-FA9C81444D11}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FE187D99-D153-4909-959C-FA9C81444D11}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FE187D99-D153-4909-959C-FA9C81444D11}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

Day11/Day11.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>

Day11/Program.cs

@@ -0,0 +1,49 @@
+var input =File.ReadAllText("input.txt").Split(' ').Select(long.Parse).ToList();
+var part1   = GetStonesAfterIteration(25, new List<long>(input)).Values.Sum().ToString();
+var part2   = GetStonesAfterIteration(75, new List<long>(input)).Values.Sum().ToString();
+
+Console.WriteLine($"Part1: {part1}\nPart2: {part2}");
+
+Dictionary<long, long> GetStonesAfterIteration(int iteration, List<long> input)
+{
+    var stones = input.ToDictionary(x => x, x => input.LongCount(y => y == x));
+    stones.TryAdd(1, 0);
+
+    for (var i = 0; i < iteration; i++)
+    {
+        var modifications = new Dictionary<long, long> { { 1, 0 } };
+        foreach (var stone in stones)
+        {
+            if (stone.Key == 0)
+            {
+                AddStone(1, stone.Value, modifications);
+            }
+            else if (stone.Key.ToString().Length % 2 == 0)
+            {
+                var stoneString = stone.Key.ToString();
+                var leftStone = int.Parse(stoneString[..(stoneString.Length / 2)]);
+                var rightStone = int.Parse(stoneString[(stoneString.Length / 2)..]);
+
+                AddStone(leftStone, stone.Value, modifications);
+                AddStone(rightStone, stone.Value, modifications);
+            }
+            else
+            {
+                AddStone(stone.Key * 2024, stone.Value, modifications);
+            }
+
+            stones.Remove(stone.Key);
+        }
+
+        foreach (var modification in modifications) stones[modification.Key] = modification.Value;
+
+        modifications.Clear();
+    }
+
+    return stones.Where(x => x.Value > 0).ToDictionary(x => x.Key, x => x.Value);
+}
+
+void AddStone(long key, long value, Dictionary<long, long> modifications)
+{
+    if (!modifications.TryAdd(key, value)) modifications[key] += value;
+}

Day11/input.txt

@@ -0,0 +1 @@
+572556 22 0 528 4679021 1 10725 2790