Merge pull request #6 from tiberiushunter/day9-2023

Day 9 2023 Solution

AdventOfCode.Solutions/_2023/Day9.cs

@@ -0,0 +1,89 @@
+using AdventOfCode.Domain.Interfaces;
+using AdventOfCode.Solutions.Helpers;
+
+namespace AdventOfCode.Solutions._2023;
+
+public class Day9 : IDay
+{
+	public string Title => "Mirage Maintenance";
+
+	public string PartA(string input)
+	{
+		var instructions = InputHelper.ToStringArray(input);
+
+		long sumOfExtrapolatedValues = 0L;
+
+		foreach (var line in instructions)
+		{
+			var parsedLine = line.Split(' ').Select(int.Parse).ToList();
+
+			var dataset = GenerateDataset(parsedLine);
+
+			for(int i = 1; i < dataset.Count; i++)
+			{
+				dataset
+					.ElementAt(i)
+					.Add(dataset.ElementAt(i).Last() + dataset.ElementAt(i - 1).Last());
+			}
+
+			sumOfExtrapolatedValues += dataset.Last().Last();
+		}
+
+		return sumOfExtrapolatedValues.ToString();
+	}
+
+	public string PartB(string input)
+	{
+		var instructions = InputHelper.ToStringArray(input);
+
+		long sumOfExtrapolatedValues = 0L;
+
+		foreach (var line in instructions)
+		{
+			var parsedLine = line.Split(' ').Select(int.Parse).ToList();
+
+			var dataset = GenerateDataset(parsedLine);
+
+			for (int i = 1; i < dataset.Count; i++)
+			{
+				dataset
+					.ElementAt(i)
+					.Insert(0, dataset.ElementAt(i).First() - dataset.ElementAt(i - 1).First());
+			}
+
+			sumOfExtrapolatedValues += dataset.Last().First();
+		}
+
+		return sumOfExtrapolatedValues.ToString();
+	}
+
+	private static List<List<int>> GenerateDataset(List<int> firstLine)
+	{
+		var dataset = new List<List<int>>
+		{
+			firstLine
+		};
+
+		while (dataset.Last().Any(x => x != 0))
+		{
+			dataset.Add(GenerateNextLine(dataset.Last()));
+		}
+
+		dataset.Reverse();
+		dataset.First().Add(0);
+
+		return dataset;
+	}
+
+	private static List<int> GenerateNextLine(List<int> line)
+	{
+		var nextLine = new List<int>();
+
+		for (int i = 0; i < line.Count - 1; i++)
+		{
+			nextLine.Add(line[i + 1] - line[i]);
+		}
+
+		return nextLine;
+	}
+}

README.md

@@ -38,7 +38,7 @@ Feel free to run through the solutions (*Note: Potential Spoilers* :see_no_evil:
 |2020|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|||||||
 |2021|:star2:|:star2:|||||||||||||||||||||||
 |2022|||||||||||||||||||||||||
-|2023|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|||||||||||||||||
+|2023|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:|:star2:||||||||||||||||
 
 <!-- GETTING STARTED -->
 ## Getting Started

Tests/AdventOfCode.Solutions.Tests/_2023/Day9Tests.cs

@@ -0,0 +1,30 @@
+namespace AdventOfCode.Solutions.Tests._2023;
+
+public class Day9Tests : DayTests
+{
+	[Test]
+	public async Task PartA()
+	{
+		// Arrange
+		string expected = "1974913025";
+
+		// Act
+		var solution = await _solverService.SolveDay(2023, 9);
+
+		// Assert
+		solution.PartA.Solution.Should().Be(expected);
+	}
+
+	[Test]
+	public async Task PartB()
+	{
+		// Arrange
+		string expected = "884";
+
+		// Act
+		var solution = await _solverService.SolveDay(2023, 9);
+
+		// Assert
+		solution.PartB.Solution.Should().Be(expected);
+	}
+}