From 14d274e5d8e27a3d2f97bcfcf4dfdeeb0783d2b3 Mon Sep 17 00:00:00 2001
From: Stefan Forstenlechner <stefanforstenlechner@gmail.com>
Date: Mon, 6 Dec 2021 20:33:52 +0100
Subject: [PATCH] Day 6

---
 Day5.cs    |  2 +-
 Day6.cs    | 34 ++++++++++++++++++++++++++++++++++
 day6/input |  1 +
 3 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 Day6.cs
 create mode 100644 day6/input

diff --git a/Day5.cs b/Day5.cs
index 732c578..80f4317 100644
--- a/Day5.cs
+++ b/Day5.cs
@@ -1,4 +1,4 @@
-#define Day5
+// #define Day5
 #define PartTwo
 #if Day5
 using System.Text.RegularExpressions;
diff --git a/Day6.cs b/Day6.cs
new file mode 100644
index 0000000..36e3c81
--- /dev/null
+++ b/Day6.cs
@@ -0,0 +1,34 @@
+#define Day6
+#if Day6
+var fish = File.ReadAllText("day6/input").Split(",")
+    .Select(long.Parse)
+    .GroupBy(x => x)
+    .ToDictionary(x => x.Key, x => x.LongCount());
+
+fish[0] = 0;
+fish[6] = 0;
+fish[7] = 0;
+fish[8] = 0;
+
+Console.WriteLine(CalculateGrowth(80, Copy(fish)));
+Console.WriteLine(CalculateGrowth(256, Copy(fish)));
+
+long CalculateGrowth(int numberOfDays, Dictionary<long, long> fishState) {
+    while (numberOfDays > 0) {
+        long newFish = fishState[0];
+        for (int i = 0; i < 8; i++) {
+            fishState[i] = fishState[i + 1];
+        }
+        fishState[6] += newFish;
+        fishState[8] = newFish;
+
+        numberOfDays--;
+    }
+    return fishState.Values.Sum();
+}
+
+Dictionary<long, long> Copy(Dictionary<long, long> dict) {
+    return dict.ToDictionary(entry => entry.Key,
+        entry => entry.Value);
+}
+#endif
\ No newline at end of file
diff --git a/day6/input b/day6/input
new file mode 100644
index 0000000..ba3c3cc
--- /dev/null
+++ b/day6/input
@@ -0,0 +1 @@
+5,4,3,5,1,1,2,1,2,1,3,2,3,4,5,1,2,4,3,2,5,1,4,2,1,1,2,5,4,4,4,1,5,4,5,2,1,2,5,5,4,1,3,1,4,2,4,2,5,1,3,5,3,2,3,1,1,4,5,2,4,3,1,5,5,1,3,1,3,2,2,4,1,3,4,3,3,4,1,3,4,3,4,5,2,1,1,1,4,5,5,1,1,3,2,4,1,2,2,2,4,1,2,5,5,1,4,5,2,4,2,1,5,4,1,3,4,1,2,3,1,5,1,3,4,5,4,1,4,3,3,3,5,5,1,1,5,1,5,5,1,5,2,1,5,1,2,3,5,5,1,3,3,1,5,3,4,3,4,3,2,5,2,1,2,5,1,1,1,1,5,1,1,4,3,3,5,1,1,1,4,4,1,3,3,5,5,4,3,2,1,2,2,3,4,1,5,4,3,1,1,5,1,4,2,3,2,2,3,4,1,3,4,1,4,3,4,3,1,3,3,1,1,4,1,1,1,4,5,3,1,1,2,5,2,5,1,5,3,3,1,3,5,5,1,5,4,3,1,5,1,1,5,5,1,1,2,5,5,5,1,1,3,2,2,3,4,5,5,2,5,4,2,1,5,1,4,4,5,4,4,1,2,1,1,2,3,5,5,1,3,1,4,2,3,3,1,4,1,1