From dd11e64c7a960e4ea453104d709828a4b4a92b17 Mon Sep 17 00:00:00 2001
From: a <a@trwnh.com>
Date: Fri, 25 Dec 2020 02:11:39 -0600
Subject: [PATCH 1/2] day 25 part 1, gotta get all 49 stars before part 2
 unlocks :(

---
 2020/25/25.py     | 22 ++++++++++++++++++++++
 2020/25/input.txt |  2 ++
 2 files changed, 24 insertions(+)
 create mode 100644 2020/25/25.py
 create mode 100644 2020/25/input.txt

diff --git a/2020/25/25.py b/2020/25/25.py
new file mode 100644
index 0000000..5691174
--- /dev/null
+++ b/2020/25/25.py
@@ -0,0 +1,22 @@
+pubkey1 = 3418282
+pubkey2 = 8719412
+
+subject = 7
+mod = 20201227
+
+loop1 = 0
+value1 = 1
+while value1 != pubkey1:
+	value1 = (value1 * subject) % mod
+	loop1 += 1
+
+loop2 = 0
+value2 = 1
+while value2 != pubkey2:
+	value2 = (value2 * subject) % mod
+	loop2 += 1
+
+enckey1 = pow(pubkey2,loop1,mod)
+enckey2 = pow(pubkey1,loop2,mod)
+assert enckey1 == enckey2
+print(enckey1)
\ No newline at end of file
diff --git a/2020/25/input.txt b/2020/25/input.txt
new file mode 100644
index 0000000..48809f6
--- /dev/null
+++ b/2020/25/input.txt
@@ -0,0 +1,2 @@
+3418282
+8719412
\ No newline at end of file

From 531b842dfc18b8a126a417262b4e33607e40fc73 Mon Sep 17 00:00:00 2001
From: a <a@trwnh.com>
Date: Fri, 25 Dec 2020 02:46:36 -0600
Subject: [PATCH 2/2] i still don't really understand this

---
 2020/21/21.py | 44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/2020/21/21.py b/2020/21/21.py
index 2bb3fc6..c08e4bf 100644
--- a/2020/21/21.py
+++ b/2020/21/21.py
@@ -1,16 +1,58 @@
 def main():
-	with open("input_sample.txt") as f:
+	with open("input.txt") as f:
 		lines = f.read().split('\n')
+	foods = [s[:-1].split(' (contains ') for s in lines]
+	# map allergens to possible ingredients
+	possible = [
+		(allergen, set(food[0].split(' ')))
+		for food in foods
+		for allergen in food[1].split(', ')
+		]
+	# get sets of all allergens and all ingredients
+	allergens = {p[0] for p in possible}
+	ingredients = set.union(*[p[1] for p in possible])
+	# find which ingredients are always listed for a given allergen
+	possible = {
+		a:set.intersection(*[
+			s[1]
+			for s in possible
+			if s[0] == a]
+		) for a in allergens
+		}
+	# reduce
+	while any({i for i in possible if len(possible[i]) > 1}):
+		for b in {j for j in possible if len(possible[j]) > 1}:
+			for a in {i for i in possible if len(possible[i]) == 1}:
+				possible[b] -= possible[a]
+	# find sets of allergenic and non-allergenic
+	unsafe = set.union(*list(possible.values()))
+	safe = ingredients - unsafe
+	#
+	print('|non-allergen occurrences| =', sum(
+		food[0].split().count(s)
+		for food in foods
+		for s in safe)
+		)
+	print('allergens:', ','.join(
+		[
+			list(possible[a])[0]
+			for a in sorted(list(possible))
+		])
+		)
+
+	"""
 	all_ingredients = set()
 	all_allergens = set()
 	may_contain = {}
 	unsafe_ingredients = {}
+	foods = []
 	for line in lines:
 		ingredients, contains = line.split(' (contains ')
 		ingredients = ingredients.split(' ')
 		contains = contains[:-1].split(', ') # remove trailing ")" then split
 		all_ingredients = all_ingredients | set(ingredients)
 		all_allergens = all_allergens | set(contains)
+	"""
 
 if __name__ == "__main__":
 	main()
\ No newline at end of file