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- import collections
- import math
- import re
- import sys
-
-
- text = sys.stdin.read()
- cookbook = {}
- for line in text.strip().splitlines():
- for i, (qty, name) in enumerate(re.findall(r'(\d+) ([A-Z]+)', line)[::-1]):
- if i == 0:
- output = name
- cookbook[output] = {output: -int(qty)}
- else:
- cookbook[output][name] = int(qty)
-
-
- def fuel_to_ore(state):
- state = collections.Counter(state)
- pending = state.copy()
- while pending:
- pending = {k: v for k, v in state.items() if k in cookbook and v > 0}
- for out, out_qty in pending.items():
- min_qty = -cookbook[out][out]
- n_times = math.ceil(out_qty / min_qty)
- state.update({k: v * n_times for k, v in cookbook[out].items()})
- return state
-
-
- def bsearch(fn, goal, lo, hi):
- while hi - lo > 1:
- mid = lo + (hi - lo) // 2
- if goal < fn(mid):
- lo, hi = lo, mid
- else:
- lo, hi = mid, hi
-
- # check
- a, b = fn(lo), fn(hi)
- assert a <= goal, 'lower bound too high'
- assert goal <= b, 'higher bound too low'
-
- return lo
-
-
- print(fuel_to_ore({'FUEL': 1})['ORE'])
- print(bsearch(lambda n: fuel_to_ore({'FUEL': n})['ORE'], 1E12, 1, 10_000_000))
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