86 lines
2.5 KiB
Python
86 lines
2.5 KiB
Python
import re
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from functools import cache
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def parse_data():
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rules = {}
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strings = []
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with open("input.txt") as file:
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for line in file:
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line = line.rstrip()
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if not line:
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continue
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if line[0].isdigit():
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rule_id, rule_or = line.split(": ")
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rule_id = int(rule_id)
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rule_or = rule_or.split(" | ")
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rule_entry = []
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if rule_or[0][0] == '"':
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rules[rule_id] = rule_or[0][1]
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else:
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for rule in rule_or:
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rule_entry.append(list(map(int, rule.split(" "))))
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rules[rule_id] = rule_entry
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else:
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strings.append(line)
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return rules, strings
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def solve_p1(rules, strings) -> int:
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@cache
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def convert_to_regex(rule_idx: int) -> str:
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rule = rules[rule_idx]
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if isinstance(rule, str):
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return rule
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else:
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out = "("
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for rule_option in rule:
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out += "".join(map(convert_to_regex, rule_option)) + "|"
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return out[:-1] + ")"
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pattern_str = convert_to_regex(0)+"$"
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pattern = re.compile(pattern_str)
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matching = 0
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for string in strings:
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if pattern.match(string):
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matching += 1
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return matching
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def solve_p2(rules, strings) -> int:
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@cache
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def convert_to_regex2(rule_idx: int) -> str:
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rule = rules[rule_idx]
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if isinstance(rule, str):
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return rule
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else:
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out = "("
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if rule_idx not in [8, 11]:
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for rule_option in rule:
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for index in rule_option:
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out += convert_to_regex2(index)
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out += "|"
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return out[:-1] + ")"
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elif rule_idx == 8:
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return out + convert_to_regex2(42) + "+)"
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elif rule_idx == 11: # I'm not proud of this at all, but it worked
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return out + convert_to_regex2(42) + f"({convert_to_regex2(42)}({convert_to_regex2(42)}({convert_to_regex2(42)}{convert_to_regex2(31)})?{convert_to_regex2(31)})?{convert_to_regex2(31)})?" + convert_to_regex2(31) + ")"
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pattern_str = convert_to_regex2(0) + "$"
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pattern = re.compile(pattern_str)
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matching = 0
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for string in strings:
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if pattern.match(string):
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matching += 1
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return matching
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RULES, STRINGS = parse_data()
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print(solve_p1(RULES, STRINGS))
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print(solve_p2(RULES, STRINGS))
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