76 lines
3.2 KiB
Plaintext
76 lines
3.2 KiB
Plaintext
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Advent of Code
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br0xen 40*
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• [About]
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• [Stats]
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• [Leaderboard]
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• [Settings]
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• [Log out]
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--- Day 11: Corporate Policy ---
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Santa's previous password expired, and he needs help choosing a new one.
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To help him remember his new password after the old one expires, Santa has devised a method of
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coming up with a password based on the previous one. Corporate policy dictates that passwords
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must be exactly eight lowercase letters (for security reasons), so he finds his new password by
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incrementing his old password string repeatedly until it is valid.
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Incrementing is just like counting with numbers: xx, xy, xz, ya, yb, and so on. Increase the
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rightmost letter one step; if it was z, it wraps around to a, and repeat with the next letter
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to the left until one doesn't wrap around.
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Unfortunately for Santa, a new Security-Elf recently started, and he has imposed some
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additional password requirements:
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• Passwords must include one increasing straight of at least three letters, like abc, bcd,
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cde, and so on, up to xyz. They cannot skip letters; abd doesn't count.
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• Passwords may not contain the letters i, o, or l, as these letters can be mistaken for
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other characters and are therefore confusing.
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• Passwords must contain at least two different, non-overlapping pairs of letters, like aa,
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bb, or zz.
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For example:
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• hijklmmn meets the first requirement (because it contains the straight hij) but fails the
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second requirement requirement (because it contains i and l).
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• abbceffg meets the third requirement (because it repeats bb and ff) but fails the first
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requirement.
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• abbcegjk fails the third requirement, because it only has one double letter (bb).
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• The next password after abcdefgh is abcdffaa.
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• The next password after ghijklmn is ghjaabcc, because you eventually skip all the passwords
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that start with ghi..., since i is not allowed.
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Given Santa's current password (your puzzle input), what should his next password be?
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Your puzzle answer was hepxxyzz.
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--- Part Two ---
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Santa's password expired again. What's the next one?
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Your puzzle answer was heqaabcc.
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Both parts of this puzzle are complete! They provide two gold stars: **
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At this point, you should return to your advent calendar and try another puzzle.
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Your puzzle input was hepxcrrq.
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You can also [Shareon Twitter Google+ Reddit] this puzzle.
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References
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Visible links
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. http://adventofcode.com/
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. http://adventofcode.com/about
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. http://adventofcode.com/stats
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. http://adventofcode.com/leaderboard
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. http://adventofcode.com/settings
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. http://adventofcode.com/auth/logout
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. http://adventofcode.com/
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. https://twitter.com/intent/tweet?text=I%27ve+completed+%22Corporate+Policy%22+%2D+Day+11+%2D+Advent+of+Code&url=http%3A%2F%2Fadventofcode%2Ecom%2Fday%2F11&related=ericwastl&hashtags=AdventOfCode
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. https://plus.google.com/share?url=http%3A%2F%2Fadventofcode%2Ecom%2Fday%2F11
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. http://www.reddit.com/submit?url=http%3A%2F%2Fadventofcode%2Ecom%2Fday%2F11&title=I%27ve+completed+%22Corporate+Policy%22+%2D+Day+11+%2D+Advent+of+Code
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