My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2016/14
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2016/day14.py
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2016/day14.py
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import sys
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import fileinput
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from hashlib import md5
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from collections import defaultdict
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from utils import memoize
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@memoize
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def salty_md5(salt, i):
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return md5(salt + str(i)).hexdigest()
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@memoize
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def stretched_md5(salt, i):
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h = salty_md5(salt, i)
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for _ in range(2016):
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h = md5(h).hexdigest()
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return h
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def first_triple(s):
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for i in range(len(s) - 2):
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a, b, c = s[i:i+3]
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if a == b == c:
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return a
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def all_quintuplets(s):
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for i in range(len(s) - 4):
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a, b, c, d, e = s[i:i+5]
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if a == b == c == d == e:
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yield a
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def find_pad_key_64(salt, hash_fn):
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valid_keys = 0
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quintuplets = defaultdict(set)
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i = 0
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while True:
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digest = hash_fn(salt, i)
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for quint in all_quintuplets(digest):
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quintuplets[i].add(quint)
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if i >= 1000:
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n = i - 1000
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triple = first_triple(hash_fn(salt, n))
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for j in range(n + 1, n + 1001):
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if triple in quintuplets[j]:
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valid_keys += 1
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sys.stdout.write('.')
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sys.stdout.flush()
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if valid_keys >= 64:
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return n
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break
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i += 1
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if __name__ == "__main__":
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SALT = fileinput.input()[0].strip()
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print "Index of 64th one-time pad key", find_pad_key_64(SALT, salty_md5)
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print "Index of key-stretched pad key", find_pad_key_64(SALT, stretched_md5)
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2016/input14.txt
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2016/input14.txt
···
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ngcjuoqr