58 lines
1.6 KiB
Python
58 lines
1.6 KiB
Python
def main():
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with open("input.txt") as f:
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lines = f.read().split('\n')
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foods = [s[:-1].split(' (contains ') for s in lines]
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# map allergens to possible ingredients
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possible = [
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(allergen, set(food[0].split(' ')))
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for food in foods
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for allergen in food[1].split(', ')
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]
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# get sets of all allergens and all ingredients
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allergens = {p[0] for p in possible}
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ingredients = set.union(*[p[1] for p in possible])
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# find which ingredients are always listed for a given allergen
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possible = {
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a:set.intersection(*[
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s[1]
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for s in possible
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if s[0] == a]
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) for a in allergens
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}
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# reduce
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while any({i for i in possible if len(possible[i]) > 1}):
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for b in {j for j in possible if len(possible[j]) > 1}:
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for a in {i for i in possible if len(possible[i]) == 1}:
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possible[b] -= possible[a]
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# find sets of allergenic and non-allergenic
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unsafe = set.union(*list(possible.values()))
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safe = ingredients - unsafe
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#
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print('|non-allergen occurrences| =', sum(
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food[0].split().count(s)
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for food in foods
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for s in safe)
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)
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print('allergens:', ','.join(
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[
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list(possible[a])[0]
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for a in sorted(list(possible))
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])
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)
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"""
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all_ingredients = set()
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all_allergens = set()
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may_contain = {}
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unsafe_ingredients = {}
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foods = []
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for line in lines:
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ingredients, contains = line.split(' (contains ')
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ingredients = ingredients.split(' ')
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contains = contains[:-1].split(', ') # remove trailing ")" then split
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all_ingredients = all_ingredients | set(ingredients)
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all_allergens = all_allergens | set(contains)
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"""
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if __name__ == "__main__":
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main() |