75 lines
2.1 KiB
Python
75 lines
2.1 KiB
Python
#!/usr/bin/env python
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import re
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from functools import reduce
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f = open("day02input.txt", "r")
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a = f.readline().strip().split(",")
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def get_re(pat_len: int, pat_num: int = 2) -> re.Pattern:
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return re.compile((r"(" + r"\d" * pat_len + r")") * pat_num)
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def part1(data: list[str]) -> int:
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bad_ids = 0
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r = {}
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for id_set in data:
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_from, _to = id_set.split("-")
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# loop over IDs in range
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for _id in range(int(_from), int(_to) + 1):
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id_len = len(str(_id))
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# weed out IDs with odd number of digits
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if id_len % 2 == 1:
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continue
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hl = str(id_len // 2)
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# check if compiled re is already in dict; add if not
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if not hl in r.keys():
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r[hl] = get_re(int(hl))
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# match ID and check if first and second halves are equal
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m = r[hl].match(str(_id))
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if m.group(1) == m.group(2):
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bad_ids += _id
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return bad_ids
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def part2(data: list[str]) -> int:
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bad_ids = set() # collect invalid IDs in a set to avoid adding counting the same ID multiple times
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r = {}
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for id_set in data:
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_from, _to = id_set.split("-")
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# loop over IDs in range
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for _id in range(int(_from), int(_to) + 1):
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id_len = len(str(_id))
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# loop over pattern lengths
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for pat_len in range(1, (id_len // 2) + 1):
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# weed out IDs where ID length is not a multiple of pattern length
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if id_len % pat_len != 0:
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continue
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pat_num = id_len // pat_len
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# check if compiled re is already in dict; add if not
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if not str(pat_len) in r.keys():
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r[str(pat_len)] = {}
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if not str(pat_num) in r[str(pat_len)].keys():
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r[str(pat_len)][str(pat_num)] = get_re(pat_len, pat_num)
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print(f"RE:\t{_id}\t\t{pat_len}\t{pat_num}\t{r[str(pat_len)][str(pat_num)]}")
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# match ID and check if all groups are equal
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m = r[str(pat_len)][str(pat_num)].match(str(_id))
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if len(set(m.groups())) == 1:
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print(f"Match:\t{_id}\t\t{pat_len}\t{pat_num}\t{r[str(pat_len)][str(pat_num)]}")
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bad_ids.add(_id)
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return sum(bad_ids)
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print(part1(a))
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print(part2(a))
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