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AdventOfCode/2020/solutions/day_21.py
2020-12-25 23:50:29 +01:00

111 lines
4.1 KiB
Python

"""AOC 2020 Day 21"""
import pathlib
import time
import collections
TEST_INPUT = """mxmxvkd kfcds sqjhc nhms (contains dairy, fish)
trh fvjkl sbzzf mxmxvkd (contains dairy)
sqjhc fvjkl (contains soy)
sqjhc mxmxvkd sbzzf (contains fish)"""
def read_input(input_path: str) -> str:
"""take input file path and return a str with the file's content"""
with open(input_path, 'r') as input_file:
input_data = input_file.read().strip()
return input_data
def extract(input_data: str) -> tuple:
"""take input data and return the appropriate data structure"""
recipes = list()
ingredient_allergenes = collections.defaultdict(set)
recipes_with_allergene = collections.defaultdict(list)
for index, recipe in enumerate(input_data.split('\n')):
ingredients, allergenes = recipe.split(' (contains ')
ingredients = set(ingredients.split())
allergenes = set(allergenes.rstrip(')').split(', '))
recipes.append(ingredients)
for ingredient in ingredients:
ingredient_allergenes[ingredient] |= allergenes
for allergene in allergenes:
recipes_with_allergene[allergene].append(index)
return recipes, ingredient_allergenes, recipes_with_allergene
def find_safe_ingredients(recipes: list, ingredient_allergenes: dict, recipes_with_allergene: dict) -> list:
"""return a list of ingredients not containing allergenes"""
safe_ingredients = list()
for ingredient, allergenes in ingredient_allergenes.items():
impossible_allergenes = set()
for allergene in allergenes:
if any(ingredient not in recipes[i] for i in recipes_with_allergene[allergene]):
impossible_allergenes.add(allergene)
allergenes -= impossible_allergenes
if not allergenes:
safe_ingredients.append(ingredient)
return safe_ingredients
def assign_allergenes(ingredient_allergenes: dict) -> dict:
"""return a dict with each ingredient and its allergene"""
assigned_allergenes = dict()
while ingredient_allergenes:
assigned_allergene = str()
assigned_ingredient = str()
for ingredient, allergenes in ingredient_allergenes.items():
if len(allergenes) == 1:
assigned_allergene = allergenes.pop()
assigned_ingredient = ingredient
break
assigned_allergenes[assigned_allergene] = assigned_ingredient
ingredient_allergenes.pop(assigned_ingredient)
for ingredient, allergenes in ingredient_allergenes.items():
if assigned_allergene in allergenes:
allergenes.remove(assigned_allergene)
return assigned_allergenes
def part1(entries: tuple) -> int:
"""part1 solver"""
recipes, ingredient_allergenes, recipes_with_allergene = entries
safe_ingredients = find_safe_ingredients(recipes, ingredient_allergenes, recipes_with_allergene)
return sum(ingredient in recipe for recipe in recipes for ingredient in safe_ingredients)
def part2(entries: tuple) -> str:
"""part2 solver"""
recipes, ingredient_allergenes, recipes_with_allergene = entries
safe_ingredients = find_safe_ingredients(recipes, ingredient_allergenes, recipes_with_allergene)
for ingredient in safe_ingredients:
ingredient_allergenes.pop(ingredient)
assigned_allergenes = assign_allergenes(ingredient_allergenes)
return ','.join(map(assigned_allergenes.get, sorted(assigned_allergenes)))
def test_input_day_21():
"""pytest testing function"""
entries = extract(TEST_INPUT)
assert part1(entries) == 5
assert part2(entries) == 'mxmxvkd,sqjhc,fvjkl'
def test_bench_day_21(benchmark):
"""pytest-benchmark function"""
benchmark(main)
def main():
"""main function"""
input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
start_time = time.time()
input_data = read_input(input_path)
entries = extract(input_data)
print("Part 1: %d" % part1(entries))
print("Part 2: %s" % part2(entries))
end_time = time.time()
print("Execution time: %f" % (end_time-start_time))
if __name__ == "__main__":
main()