37 lines
2.2 KiB
Plaintext
37 lines
2.2 KiB
Plaintext
--- Day 5: Doesn't He Have Intern-Elves For This? ---
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Santa needs help figuring out which strings in his text file are naughty or nice.
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A nice string is one with all of the following properties:
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It contains at least three vowels (aeiou only), like aei, xazegov, or aeiouaeiouaeiou.
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It contains at least one letter that appears twice in a row, like xx, abcdde (dd), or aabbccdd (aa, bb, cc, or dd).
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It does not contain the strings ab, cd, pq, or xy, even if they are part of one of the other requirements.
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For example:
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ugknbfddgicrmopn is nice because it has at least three vowels (u...i...o...), a double letter (...dd...), and none of the disallowed substrings.
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aaa is nice because it has at least three vowels and a double letter, even though the letters used by different rules overlap.
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jchzalrnumimnmhp is naughty because it has no double letter.
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haegwjzuvuyypxyu is naughty because it contains the string xy.
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dvszwmarrgswjxmb is naughty because it contains only one vowel.
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How many strings are nice?
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Your puzzle answer was 238.
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--- Part Two ---
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Realizing the error of his ways, Santa has switched to a better model of determining whether a string is naughty or nice. None of the old rules apply, as they are all clearly ridiculous.
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Now, a nice string is one with all of the following properties:
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It contains a pair of any two letters that appears at least twice in the string without overlapping, like xyxy (xy) or aabcdefgaa (aa), but not like aaa (aa, but it overlaps).
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It contains at least one letter which repeats with exactly one letter between them, like xyx, abcdefeghi (efe), or even aaa.
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For example:
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qjhvhtzxzqqjkmpb is nice because is has a pair that appears twice (qj) and a letter that repeats with exactly one letter between them (zxz).
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xxyxx is nice because it has a pair that appears twice and a letter that repeats with one between, even though the letters used by each rule overlap.
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uurcxstgmygtbstg is naughty because it has a pair (tg) but no repeat with a single letter between them.
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ieodomkazucvgmuy is naughty because it has a repeating letter with one between (odo), but no pair that appears twice.
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How many strings are nice under these new rules?
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Your puzzle answer was 69.
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Both parts of this puzzle are complete! They provide two gold stars: ** |