| 12345678910111213141516171819202122232425262728 |
- #!/usr/bin/env python3
- import sys
- from collections import Counter
- def parse(f):
- yield next(f).rstrip()
- next(f)
- yield dict(line.rstrip().split(' -> ') for line in f)
- def grow(polymer, rules, steps):
- elements = Counter(polymer)
- pairs = Counter(polymer[i:i + 2] for i in range(len(polymer) - 1))
- for step in range(steps):
- for pair, num in list(pairs.items()):
- if num and pair in rules:
- a, b = pair
- c = rules[pair]
- pairs[pair] -= num
- pairs[a + c] += num
- pairs[c + b] += num
- elements[c] += num
- return max(elements.values()) - min(elements.values())
- template, rules = parse(sys.stdin)
- print(grow(template, rules, 10))
- print(grow(template, rules, 40))
|
