Completed Day 1

AdventOfCode2024/Day1/Day1.csproj

@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\AdventOfCode2024.Input\AdventOfCode2024.Input.csproj" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <Content Include="..\..\input\day1.txt">
+        <Link>input\day1.txt</Link>
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+      </Content>
+      <Content Include="..\..\input\day1sample.txt">
+        <Link>input\day1sample.txt</Link>
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+      </Content>
+      <Content Include="..\..\input\_placeholder">
+        <Link>input\_placeholder</Link>
+      </Content>
+    </ItemGroup>
+    
+</Project>

AdventOfCode2024/Day1/DayOne.cs

@@ -0,0 +1,70 @@
+namespace Day1;
+
+// Advent of Code 2024
+// Day 1
+// James Plante (jwplante)
+
+class DayOne
+{
+    private static async Task PartOne()
+    {
+        await using FileStream inputStream = File.OpenRead("input/day1.txt");
+        PairParser parser = new();
+        
+        IList<(int, int)> entries = await parser.ParseAsync(inputStream);
+        
+        // Given the parsed entries, add them to two new lists and sort them
+        List<int> leftList = [];
+        List<int> rightList = [];
+        foreach ((int left, int right) in entries)
+        {
+            leftList.Add(left);
+            rightList.Add(right);
+        }
+        leftList.Sort();
+        rightList.Sort();
+
+        // Convert back into pairs of (smallest, smallest), (secondSmallest, ...
+        List<(int, int)> sortedPairs = leftList
+            .Zip(rightList, (left, right) => (left, right))
+            .ToList();
+       
+        long totalDistance = 0;
+        foreach ((int left, int right) in sortedPairs)
+        {
+            var lineDistance = Math.Abs(left - right);
+            totalDistance += lineDistance;
+        }
+
+        Console.WriteLine($"Part 1: The total distance of the lines is {totalDistance}.");
+    }
+    
+    private static async Task PartTwo()
+    {
+        await using FileStream inputStream = File.OpenRead("input/day1.txt");
+        PairParser parser = new();
+        
+        IList<(int, int)> entries = await parser.ParseAsync(inputStream);
+        
+        // Get the frequencies for the right list
+        Dictionary<int, int> frequencies = [];
+        foreach ((_, int right) in entries)
+        {
+            frequencies[right] = frequencies.GetValueOrDefault(right) + 1;
+        }
+
+        long similarityScore = 0;
+        foreach ((int left, _) in entries)
+        {
+            var intermediateScore = left * frequencies.GetValueOrDefault(left);
+            similarityScore += intermediateScore;
+        }
+        Console.WriteLine($"Part 2: The total similarity score is {similarityScore}.");
+    }
+    
+    public static async Task Main(string[] args)
+    {
+        await PartOne();
+        await PartTwo();
+    }
+}

AdventOfCode2024/Day1/PairParser.cs

@@ -0,0 +1,27 @@
+using AdventOfCode2024.Input.Parsers;
+
+namespace Day1;
+
+/// <summary>
+/// Parses a Stream line by line for pairs of integers
+/// </summary>
+public class PairParser : TextLineParser<(int, int)>
+{
+    protected override (int, int) ParseLine(string line)
+    {
+        var pair = line.Split(" ", StringSplitOptions.RemoveEmptyEntries);
+        if (pair.Length < 2)
+        {
+            throw new ArgumentException("Invalid line");
+        }
+
+        var entryOneParsed = int.TryParse(pair[0], out var entryOne);
+        var entryTwoParsed = int.TryParse(pair[1], out var entryTwo);
+        if (!entryOneParsed || !entryTwoParsed)
+        {
+            throw new ArgumentException("Invalid line");
+        }
+
+        return (entryOne, entryTwo);
+    }
+}