2018 Day14 Solved (little slow, but OK)

Data/2018_14.txt

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+846601

Solutions/2018/Day14.cs

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+namespace AdventOfCode.Solutions._2018;
+
+/// <summary>
+/// Day 14: Chocolate Charts
+/// https://adventofcode.com/2018/day/14
+/// </summary>
+[Description("Chocolate Charts")]
+public sealed partial class Day14 {
+
+	public static string Part1(string[] input, params object[]? _) => Solution1(input).ToString();
+	public static string Part2(string[] input, params object[]? _) => Solution2(input).ToString();
+
+	private static string Solution1(string[] input) {
+		int noOfRecipes = input[0].AsInt();
+
+		LinkedList<int> recipes = new([3, 7]);
+		string tail = "37";
+		List<LinkedListNode<int>> elfCurrentRecipes = [recipes.First!, recipes.Last!];
+
+		do {
+			_ = CreateNewRecipes(recipes, elfCurrentRecipes, tail);
+		} while (recipes.Count < noOfRecipes + 10);
+
+		return string.Join("", recipes.Skip(noOfRecipes).Take(10));
+	}
+
+	private static int Solution2(string[] input) {
+		string recipesToFind = input[0];
+
+		LinkedList<int> recipes = new([3, 7]);
+		string tail = "37";
+		List<LinkedListNode<int>> elfCurrentRecipes = [recipes.First!, recipes.Last!];
+
+		do {
+			tail = CreateNewRecipes(recipes, elfCurrentRecipes, tail);
+		} while (!tail.Contains(recipesToFind));
+
+		return string.Join("", recipes).IndexOf(recipesToFind);
+	}
+
+	private static string CreateNewRecipes(LinkedList<int> recipes, List<LinkedListNode<int>> elfCurrentRecipes, string tail)
+	{
+		string newRecipes = elfCurrentRecipes.Select(x => x.Value).Sum().ToString();
+		for (int i = 0; i < newRecipes.Length; i++) {
+			_ = recipes.AddLast(newRecipes[i].ToString().AsInt());
+			tail += newRecipes[i];
+		}
+
+		for (int i = 0; i < elfCurrentRecipes.Count; i++) {
+			LinkedListNode<int> recipe = elfCurrentRecipes[i];
+			int noOfSteps = recipe.Value + 1;
+			for (int steps = 0; steps < noOfSteps; steps++) {
+				recipe = recipe.Next ?? recipes.First!;
+			}
+			elfCurrentRecipes[i] = recipe;
+		}
+
+		return tail.Length > 9 ? tail[^9..] : tail;
+	}
+
+
+}

Tests/2018/Tests_14.cs

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+namespace AdventOfCode.Tests.Year2018;
+
+public class Tests_14_Chocolate_Charts
+{
+	const int DAY = 14;
+
+	[Theory]
+	[InlineData("9", "5158916779")]
+	[InlineData("5", "0124515891")]
+	[InlineData("18", "9251071085")]
+	[InlineData("2018", "5941429882")]
+	public void Part1(string input, string expected)
+	{
+		string actual = SolutionRouter.SolveProblem(YEAR, DAY, PART1, input);
+		Assert.Equal(expected, actual);
+	}
+
+	[Theory]
+	[InlineData("51589", 9 )]
+	[InlineData("01245", 5 )]
+	[InlineData("92510", 18)]
+	[InlineData("59414", 2018)]
+	public void Part21(string input, int expected)
+	{
+		_ = int.TryParse(SolutionRouter.SolveProblem(YEAR, DAY, PART2, input), out int actual);
+		Assert.Equal(expected, actual);
+	}
+
+}