2020aoc/day21.py

87 lines
2.6 KiB
Python

import collections
def read_food():
with open('day21/input') as reader:
return reader.readlines()
food_as_text = read_food()
food = []
for f in food_as_text:
ingredients, allergens = f[:-1].split(' (contains ')
food.append((ingredients.split(' '), allergens[:-1].split(', ')))
def get_allergen_possibilities(food):
allergen_possibilities = {}
for ingredients, allergens in food:
for a in allergens:
if a not in allergen_possibilities.keys():
allergen_possibilities[a] = set(ingredients)
else:
allergen_possibilities[a] = allergen_possibilities[a].intersection(set(ingredients))
return allergen_possibilities
def get_all_ingredients_with_possible(allergen_possibilities):
all_ingredients_with_possible = set()
for i in allergen_possibilities.values():
all_ingredients_with_possible = all_ingredients_with_possible.union(i)
return all_ingredients_with_possible
def get_all_ingredients(food):
all_ingredients = set()
for ingredients, allergens in food:
all_ingredients = all_ingredients.union(ingredients)
return all_ingredients
def count_no_allergens(food, no_allergen):
c = 0
for ingredients, allergens in food:
for i in ingredients:
if i in no_allergen:
c += 1
return c
def find_allergens(allergen_possibilities):
defined_allergens = {}
while True:
found_key, found_value = next((key, value) for key, value in allergen_possibilities.items() if len(value) == 1)
ingredient_defined = list(found_value)[0]
defined_allergens[found_key] = ingredient_defined
del allergen_possibilities[found_key]
for allergen in allergen_possibilities.keys():
if ingredient_defined in allergen_possibilities[allergen]:
allergen_possibilities[allergen].remove(ingredient_defined)
if not allergen_possibilities:
break
return defined_allergens
allergen_possibilities = get_allergen_possibilities(food)
all_ingredients_with_possible = get_all_ingredients_with_possible(allergen_possibilities)
all_ingredients = get_all_ingredients(food)
no_allergen = all_ingredients.difference(all_ingredients_with_possible)
res = count_no_allergens(food, no_allergen)
print(res)
defined_allergens = find_allergens(allergen_possibilities)
ordered_by_insertion = collections.OrderedDict(sorted(defined_allergens.items()))
canonical_dangerous_ingredient_list = ','.join([v for v in ordered_by_insertion.values()])
print(canonical_dangerous_ingredient_list)