44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
import re
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from collections import defaultdict
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LINE_RE = re.compile(r"^(\w+ \w+) bags contain (.+)\.$")
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CONT_RE = re.compile(r"(\d+) (\w+ \w+) bags?")
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def main():
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with open("day7.txt", "rt") as f:
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lines = [line.rstrip() for line in f.readlines()]
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rules = defaultdict(dict)
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for line in lines:
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match = LINE_RE.match(line)
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subject, contained = match.groups()
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contained = contained.split(", ")
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for c in contained:
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match = CONT_RE.match(c)
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if match:
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cn, ct = match.groups()
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rules[subject][ct] = int(cn)
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# Part 1
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num_containers = sum(contain_shiny_gold(bag, rules) for bag in rules.copy())
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print("Containing at least 1 shiny gold:", num_containers)
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# Part 2
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inside_shiny_gold = count_bags("shiny gold", rules) - 1
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print("Inside shiny gold:", inside_shiny_gold)
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def contain_shiny_gold(bag, rules):
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if "shiny gold" in rules[bag]:
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return True
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return any(contain_shiny_gold(b, rules) for b in rules[bag])
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def count_bags(bag, rules):
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return sum(count_bags(b, rules) * rules[bag][b] for b in rules[bag]) + 1
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if __name__ == "__main__":
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main()
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