day 22 part 2 in progress

AdventOfCode/Day22.cs

@@ -1,4 +1,7 @@
 
+using System.Collections.Generic;
+using static System.Runtime.InteropServices.JavaScript.JSType;
+
 namespace AdventOfCode;
 
 public class Day22 : BaseDay
@@ -14,26 +17,68 @@ public override ValueTask<string> Solve_1()
 
     public override ValueTask<string> Solve_2()
     {
-        return new("");
+        long[] numbers = File.ReadAllLines(InputFilePath).Select(long.Parse).ToArray();
+
+
+        Dictionary<(int, int, int, int), int> bananas = new Dictionary<(int, int, int, int), int>();
+        foreach (long n in numbers)
+        {
+            (int, int)[] changes = GetPricesWithChanges(n, 2000);
+
+            for (int i = 0; i < changes.Length - 3; ++i)
+            {
+                if (!bananas.TryAdd((changes[i].Item2, changes[i+1].Item2, changes[i+2].Item2, changes[i+3].Item2), changes[i+3].Item1))
+                {
+                    bananas[(changes[i].Item2, changes[i + 1].Item2, changes[i + 2].Item2, changes[i + 3].Item2)] += changes[i + 3].Item1;
+                }
+            }
+        }
+
+        int max = bananas.Max(b => b.Value);
+
+        return new(max.ToString());
     }
 
     private long GetIteration(long number, int iterations)
     {
         for (int i = 0; i < iterations; ++i)
         {
-            // 1
-            number = (number << 6) ^ number;
-            number = number % 16777216;
+            number = GetNext(number);
+        }
+
+        return number;
+    }
 
-            // 2
-            number = (number / 32) ^ number;
-            number = number % 16777216;
+    private (int, int)[] GetPricesWithChanges(long number, int iterations)
+    {
+        (int, int)[] priceChanges = new (int, int)[iterations];
+        int prevDigit = (int)(number % 10);
 
-            // 3
-            number = (number << 11) ^ number;
-            number = number % 16777216;
+        for (int i = 0; i < iterations; ++i)
+        {
+            number = GetNext(number);
+            int currDigit = (int)(number % 10);
+            priceChanges[i] = (currDigit, currDigit - prevDigit);
+            prevDigit = currDigit;
         }
 
+        return priceChanges;    
+    }
+
+    private long GetNext(long number)
+    {
+        // 1
+        number = (number << 6) ^ number;
+        number = number % 16777216;
+
+        // 2
+        number = (number / 32) ^ number;
+        number = number % 16777216;
+
+        // 3
+        number = (number << 11) ^ number;
+        number = number % 16777216;
+
         return number;
     }
 }