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- import argparse
- import functools
- from typing import NamedTuple, List, Dict, Set, Tuple, Optional
- from collections import Counter, defaultdict
- import sys
- from functools import lru_cache
- parser = argparse.ArgumentParser()
- parser.add_argument("ifile", type=argparse.FileType('r'))
- args = parser.parse_args()
- pair_rules: Dict[str, str] = dict()
- template = args.ifile.readline().strip()
- args.ifile.readline() # skip blank line
- for line in args.ifile.readlines():
- chunks = line.strip().split(" ")
- pair_rules[chunks[0]] = chunks[2]
- def polymerize(template: str):
- global pair_rules
- constructed = "" + template[0]
- prev = template[0]
- for index in range(1, len(template)):
- constructed += pair_rules.get(prev + template[index], "")
- prev = template[index]
- constructed += template[index]
- return constructed
- @lru_cache(2048)
- def polyCount(template: str, steps: int):
- polymer = polymerize(template)
- if steps == 1:
- return Counter(polymer)
- stuff = [polyCount(polymer[index] + polymer[index + 1], steps - 1) for index in range(0, len(polymer) - 1)]
- return functools.reduce(lambda acc, val: acc + val, stuff) - Counter(polymer[1:-1])
- counts = polyCount(template, 40).most_common()
- print(counts[0][1] - counts[-1][1])
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