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- #!/usr/bin/env python3
- import sys
- from collections import defaultdict
- def read_graph(f):
- graph = {'ORE': (1, {})}
- for line in f:
- lhs, rhs = line.strip().split(' => ')
- noutp, outp = rhs.split()
- assert outp not in graph
- edges = {}
- for inp in lhs.split(', '):
- ninp, inp = inp.split()
- edges[inp] = int(ninp)
- graph[outp] = int(noutp), edges
- return graph
- def ore_needed(reactions, fuel):
- def produce(outp, amount):
- from_stash = min(amount, stash[outp])
- stash[outp] -= from_stash
- amount -= from_stash
- noutp, inputs = reactions[outp]
- multiplier = amount // noutp + bool(amount % noutp)
- for inp, ninp in inputs.items():
- produce(inp, ninp * multiplier)
- stash[outp] += noutp * multiplier - amount
- produced[outp] += amount
- stash = defaultdict(int)
- produced = defaultdict(int)
- produce('FUEL', fuel)
- return produced['ORE']
- def fuel_with_ore(reactions, ore):
- fuel = 0
- step = ore
- while step:
- while ore_needed(reactions, fuel) < ore:
- fuel += step
- fuel -= step
- step //= 2
- return fuel
- reactions = read_graph(sys.stdin)
- print(ore_needed(reactions, 1))
- print(fuel_with_ore(reactions, 1000000000000))
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