From add3743091dee570e63ad5c0c2c953b58896f1cc Mon Sep 17 00:00:00 2001
From: Amatsugu <khamraj@kaisei.app>
Date: Sun, 1 Dec 2024 00:13:50 -0500
Subject: [PATCH] Day 1

---
 AdventOfCode/AdventOfCode.csproj              |  2 +-
 .../AOC2024/Day1/HistorianHysteria.cs         | 40 +++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 AdventOfCode/Problems/AOC2024/Day1/HistorianHysteria.cs

diff --git a/AdventOfCode/AdventOfCode.csproj b/AdventOfCode/AdventOfCode.csproj
index a96ed50..3d8672d 100644
--- a/AdventOfCode/AdventOfCode.csproj
+++ b/AdventOfCode/AdventOfCode.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
 	<OutputType>Exe</OutputType>
-	<TargetFramework>net8.0</TargetFramework>
+	<TargetFramework>net9.0</TargetFramework>
 	<ImplicitUsings>enable</ImplicitUsings>
 	<Nullable>enable</Nullable>
   </PropertyGroup>
diff --git a/AdventOfCode/Problems/AOC2024/Day1/HistorianHysteria.cs b/AdventOfCode/Problems/AOC2024/Day1/HistorianHysteria.cs
new file mode 100644
index 0000000..0c4dcc2
--- /dev/null
+++ b/AdventOfCode/Problems/AOC2024/Day1/HistorianHysteria.cs
@@ -0,0 +1,40 @@
+using AdventOfCode.Runner.Attributes;
+
+using System;
+using System.Collections.Frozen;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AdventOfCode.Problems.AOC2024.Day1;
+[ProblemInfo(2024, 1, "Historian Hysteria")]
+internal class HistorianHysteria : Problem<int, int>
+{
+	private int[] _left = [];
+	private int[] _right = [];
+
+	public override void CalculatePart1()
+	{
+		Part1 = _left.Order()
+			.Zip(_right.Order())
+			.Select(a => Math.Abs(a.First - a.Second))
+			.Sum();
+	}
+
+	public override void CalculatePart2()
+	{
+		var rightFeq = _right.GroupBy(x => x)
+			.ToFrozenDictionary(g => g.Key, g => g.Count());
+		Part2 = _left.Select(x => rightFeq.TryGetValue(x, out var f) ? f * x : 0)
+			.Sum();
+	}
+
+	public override void LoadInput()
+	{
+		var lines = ReadInputLines("input.txt");
+		var data = lines.Select(l => l.Split(' ').Select(int.Parse)).ToList();
+		_left = data.Select(l => l.First()).ToArray();
+		_right = data.Select(l => l.Last()).ToArray();
+	}
+}