51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
#!/usr/bin/env python
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from collections import defaultdict
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import regex
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import sys
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RULE_REGEX = regex.compile(r'(.*) bags contain (?:(no|\d+) (.*?) bags?(?:, )?)+\.')
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def process_rules(rules):
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rules_dict = {}
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for rule in rules:
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m = regex.fullmatch(RULE_REGEX, rule)
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if m is None:
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raise ValueError(f"Couldn't parse rule: {rule!r}")
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colour = m.group(1)
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child_nums = m.captures(2)
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child_colours = m.captures(3)
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children = {}
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for n, c in zip(child_nums, child_colours):
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if n == 'no':
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continue
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children[c] = int(n)
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rules_dict[colour] = children
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return rules_dict
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def parents_of(rules, colour):
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parents = set()
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for parent, children in rules.items():
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if colour in children:
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parents.add(parent)
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parents |= parents_of(rules, parent)
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return parents
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def children_of(rules, colour):
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children = defaultdict(lambda: 0)
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for child_colour, child_num in rules[colour].items():
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children[child_colour] += child_num
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for col, num in children_of(rules, child_colour).items():
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children[col] += child_num * num
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return children
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if __name__ == '__main__':
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bag_rules = [rule.strip() for rule in sys.stdin.readlines()]
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rules = process_rules(bag_rules)
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print(len(parents_of(rules, 'shiny gold')))
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print(sum(children_of(rules, 'shiny gold').values()))
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