1 files changed, 45 insertions, 0 deletions
diff --git a/2015/13/puzzles.py b/2015/13/puzzles.py
new file mode 100644
index 0000000..33e49e1
--- /dev/null
+++ b/2015/13/puzzles.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+
+import re
+from collections import defaultdict
+from itertools import permutations
+from typing import DefaultDict
+
+
+def main() -> None:
+	with open("input", "r", encoding="utf-8") as f:
+		entries = list(
+			map(
+				lambda e: [e[0], e[1], int(e[2]) if e[1] == "gain" else -int(e[2]), e[3]],
+				(
+					re.split(
+						r"([^ ]+) would (gain|lose) (\d+) happiness units by sitting next to ([^"
+						r" ]+).\n",
+						line,
+					)[1:-1]
+					for line in f.readlines()
+				),
+			)
+		)
+
+	emap: DefaultDict[str, dict[str, int]] = defaultdict(lambda: {})
+	for entry in entries:
+		emap[entry[0]][entry[3]] = entry[2]
+		# START PART 2
+		emap[entry[0]]["Me"] = 0
+		emap["Me"][entry[0]] = 0
+		# END PART 2
+
+	print(
+		max(
+			sum(
+				emap[pair[0]][pair[1]] + emap[pair[1]][pair[0]]
+				for pair in tuple(zip(perm, perm[1:])) + ((perm[-1], perm[0]),)
+			)
+			for perm in permutations(emap)
+		)
+	)
+
+
+if __name__ == "__main__":
+	main()