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#!/usr/bin/env python3
from collections import OrderedDict
from itertools import product
# START PART 2
from re import search
def check(test: str, patterns: dict[str, list[str]]) -> bool:
chunks = string_divide(test, 8)
search_str = ""
for chunk in chunks:
if chunk in patterns["42"]:
search_str += "0"
elif chunk in patterns["31"]:
search_str += "1"
else:
return False
# 42 = 0, 31 = 1
res = search(r"^(0)+(1)+$", search_str)
return not (not res or search_str.count("0") <= search_str.count("1"))
def string_divide(string: str, div: int) -> list[str]:
l: list[str] = []
for i in range(0, len(string), div):
l.append(string[i : i + div])
return l
# END PART 2
def main() -> None:
with open("input", "r", encoding="utf-8") as f:
data = f.readlines()
i = 0
rules: list[tuple[str]] = []
while data[i] != "\n":
rules.append(tuple(x for x in tuple(data[i].split(": "))))
i += 1
tests = [line.strip() for line in data]
patterns: dict[str, list[str]] = {}
# Get "a" and "b" out of the way to do less comparisons in the next loop. Also make use of
# this loop to strip newlines off of all the rules.
for rule in rules:
rules[rules.index(rule)] = (rule[0], rule[1].strip())
if len(rule[1]) == 4:
patterns[rule[0]] = [rule[1][1]]
while len(patterns) != len(rules):
for rule in rules:
if rule[0] in patterns:
continue
res = rule[1].split(" | ")
if all(req in patterns for req in list(OrderedDict.fromkeys(" ".join(res).split(" ")))):
all_combos: list[str] = []
for re in res:
re = re.split(" ")
if len(re) == 1:
all_combos.extend(patterns[re[0]])
else:
all_combos = list(
OrderedDict.fromkeys(
all_combos
+ [f"{x}{y}" for x, y in product(patterns[re[0]], patterns[re[1]])]
)
)
patterns[rule[0]] = all_combos
# START PART 1
print(len([test for test in tests if test in patterns["0"]]))
# END PART 1 START PART 2
print(len([test for test in tests if check(test, patterns)]))
# END PART 2
if __name__ == "__main__":
main()
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