56 lines
1.1 KiB
Python
56 lines
1.1 KiB
Python
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#!/usr/bin/python
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# solution borrowd from
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# https://www.reddit.com/r/adventofcode/comments/3xflz8/day_19_solutions/?sort=new
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import re
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from random import shuffle
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RE_RULE = re.compile(r'^(.*) => (.*)$')
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def read_file(filename):
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file = open(filename, 'r')
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while True:
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line = file.readline()
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if not line:
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break
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yield line.strip()
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def find_formula(formula, rules):
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steps = 0
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f = formula
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while formula != 'e':
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start = formula
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for k,v in rules:
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if v in formula:
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steps += 1
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formula = formula.replace(v, k, 1)
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if formula == start:
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shuffle(rules)
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steps = 0
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formula = f
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return steps
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def main():
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medicine = ""
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rules = []
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for line in read_file('input'):
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# skip empty lines
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if not line:
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continue
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match = re.match(RE_RULE, line)
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if match:
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rules.append((match.group(1), match.group(2)))
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else:
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medicine = line
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print rules
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print medicine
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print find_formula(medicine, rules)
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if __name__ == "__main__":
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main()
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