Add Day 06 solution, needs cleanup later

AoC_2025/Day06.cs

@@ -0,0 +1,76 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using AdvenOfCode.Contracts;
+using Coordinate = (int x, int y);
+
+namespace AoC_2025;
+
+public class Day06 : IPuzzleSolver<long>
+{
+    private (string[] operands, string[] numbers) ParsePuzzleInput(string path)
+    {
+        var puzzleInput = File.ReadAllLines(path)
+            .Where(line => !string.IsNullOrWhiteSpace(line))
+            .ToArray();
+        var operands = puzzleInput[^1]
+            .Split(' ', StringSplitOptions.RemoveEmptyEntries);
+        var numbers = puzzleInput[..^1];
+        return (operands, numbers);
+    }
+
+    public long SolvePart1(string pathToPuzzleInput)
+    {
+        var calculations = ParsePuzzleInput(pathToPuzzleInput);
+        var numbers = calculations.numbers
+            .Select(line => line.Split(' ', StringSplitOptions.RemoveEmptyEntries))
+            .Select(line => line.Index().ToArray())
+            .SelectMany(tuples => tuples.Select(tuple => (tuple.Index, long.Parse(tuple.Item))).ToArray())
+            .ToArray();
+        var pivotedNumbers = numbers.GroupBy(tuple => tuple.Index);
+        var indexedOperands = calculations.operands
+            .Index()
+            .Select(tuple => (tuple.Index, ParseOperand(tuple.Item)))
+            .ToDictionary();
+        var results = pivotedNumbers.Select(group =>
+            group
+                .Select(tuple => tuple.Item2)
+                .Aggregate(indexedOperands[group.Key].opBaseValue,
+                    (acc, number) => indexedOperands[group.Key].operation(acc, number)));
+        return results.Sum();
+    }
+    
+    public long SolvePart2(string pathToPuzzleInput)
+    {
+        var calculations = ParsePuzzleInput(pathToPuzzleInput);
+        var operands = calculations.operands.Select(ParseOperand).Reverse().ToArray();
+        List<List<long>> numberColumns = [];
+        List<long> currentColumn = [];
+        for (var i = 1; i <= calculations.numbers[0].Length; i++)
+        {
+            var current = calculations.numbers.Aggregate("", (current1, number) => current1 + number[^i]);
+
+            if (!string.IsNullOrWhiteSpace(current))
+            {
+                currentColumn.Add(long.Parse(current));
+            }
+            else
+            {
+                numberColumns.Add(currentColumn);
+                currentColumn = [];
+            }
+        }
+        numberColumns.Add(currentColumn);
+
+        return numberColumns
+            .Select((column, colIndex) => column.Aggregate(operands[colIndex].opBaseValue, (acc, next) => operands[colIndex].operation(acc, next)))
+            .Sum();
+    }
+
+    private (Func<long, long, long> operation, long opBaseValue) ParseOperand(string operand) => operand switch
+    {
+        "+" => ((long a, long b) => a + b, 0),
+        "*" => ((long a, long b) => a * b, 1),
+        _ => throw new ArgumentOutOfRangeException(nameof(operand))
+    };
+}