From b03404fe6a9cfbd73d694d06589a3101835536d6 Mon Sep 17 00:00:00 2001
From: Sebastian Lindemeier <lindemeier.sebastian@bgetem.de>
Date: Sat, 6 Dec 2025 13:55:52 +0100
Subject: [PATCH] Refactor Day06 to use LINQ for parsing numbers by column

---
 AoC_2025/Day06.cs | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/AoC_2025/Day06.cs b/AoC_2025/Day06.cs
index 1f3d299..7bc4bb0 100644
--- a/AoC_2025/Day06.cs
+++ b/AoC_2025/Day06.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Data.Common;
 using System.IO;
 using System.Linq;
 using AdvenOfCode.Contracts;
@@ -65,26 +66,13 @@ public class Day06 : IPuzzleSolver<long>
 
     private static long[][] ParseNumbersByColumn(string[] numberLines)
     {
-        List<long[]> numberColumns = [];
-        List<long> currentColumn = [];
-        for (var i = 1; i <= numberLines[0].Length; i++)
-        {
-            var nextNumber = numberLines.Aggregate("", (acc, numberLine) => acc + numberLine[^i]);
-
-            if (!string.IsNullOrWhiteSpace(nextNumber))
-            {
-                currentColumn.Add(long.Parse(nextNumber));
-            }
-            else
-            {
-                numberColumns.Add(currentColumn.ToArray());
-                currentColumn = [];
-            }
-        }
-        numberColumns.Add(currentColumn.ToArray());
-        
-        numberColumns.Reverse();
-        return numberColumns.ToArray();
+        var (numberColumns, lastColumn) = Enumerable.Range(1, numberLines[0].Length)
+            .Select(i => numberLines.Aggregate("", (acc, numberLine) => acc + numberLine[^i]))
+            .Aggregate((columns: (List<long[]>)[[]], column: (long[])[]),
+                (acc, number) => string.IsNullOrWhiteSpace(number) 
+                    ? ([..acc.columns, acc.column], []) 
+                    : (acc.columns, [..acc.column, long.Parse(number)]));
+        return [lastColumn, ..Enumerable.Reverse(numberColumns)];
     }
 
     private (Func<long, long, long> operation, long opBaseValue) ParseOperand(string operand) => operand switch