From 1ac455d7a191b52020aac0d6f408febc14a37993 Mon Sep 17 00:00:00 2001
From: Benjo <benjamin.kraft@online.de>
Date: Sun, 12 Dec 2021 11:49:05 +0100
Subject: [PATCH] day 12

---
 12/12.py     | 31 +++++++++++++++++++++++++++++++
 12/input     | 24 ++++++++++++++++++++++++
 12/testInput |  7 +++++++
 3 files changed, 62 insertions(+)
 create mode 100644 12/12.py
 create mode 100644 12/input
 create mode 100644 12/testInput

diff --git a/12/12.py b/12/12.py
new file mode 100644
index 0000000..aa80e1b
--- /dev/null
+++ b/12/12.py
@@ -0,0 +1,31 @@
+
+with open("input") as file:
+	lines = file.read().splitlines()
+	edges = [set(line.split("-")) for line in lines]
+
+
+def getAdjacent(knot: str) -> set[str]:
+	return {edge.difference({knot}).pop() for edge in edges if knot in edge}
+
+
+def solve():
+	def find(knot: str, visited: set[str], smallUsedTwice: bool) -> set[tuple[str, ...]]:
+		if knot == "end":
+			return {"end"}
+		foundPaths = set()
+		newVisited = visited.union({knot}) if knot.islower() else visited
+		for k in getAdjacent(knot).difference(visited):
+			if knot.islower() and not smallUsedTwice and knot != "start":
+				for p in find(k, visited, True):
+					foundPaths.add((knot, *p))
+			for p in find(k, newVisited, smallUsedTwice):
+				foundPaths.add((knot, *p))
+		return foundPaths
+
+	paths1 = find("start", set(), True)
+	paths2 = find("start", set(), False)
+
+	print(len(paths1), len(paths2))
+
+
+solve()
diff --git a/12/input b/12/input
new file mode 100644
index 0000000..52cfe6a
--- /dev/null
+++ b/12/input
@@ -0,0 +1,24 @@
+EG-bj
+LN-end
+bj-LN
+yv-start
+iw-ch
+ch-LN
+EG-bn
+OF-iw
+LN-yv
+iw-TQ
+iw-start
+TQ-ch
+EG-end
+bj-OF
+OF-end
+TQ-start
+TQ-bj
+iw-LN
+EG-ch
+yv-iw
+KW-bj
+OF-ch
+bj-ch
+yv-TQ
diff --git a/12/testInput b/12/testInput
new file mode 100644
index 0000000..898cd56
--- /dev/null
+++ b/12/testInput
@@ -0,0 +1,7 @@
+start-A
+start-b
+A-c
+A-b
+b-d
+A-end
+b-end
\ No newline at end of file