63 lines
3.0 KiB
Plaintext
63 lines
3.0 KiB
Plaintext
Advent of Code
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--- Day 7: Internet Protocol Version 7 ---
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While snooping around the local network of EBHQ, you compile a list of IP addresses (they're IPv7, of course; IPv6 is much too limited).
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You'd like to figure out which IPs support TLS (transport-layer snooping).
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An IP supports TLS if it has an Autonomous Bridge Bypass Annotation, or ABBA. An ABBA is any four-character sequence which consists of a
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pair of two different characters followed by the reverse of that pair, such as xyyx or abba. However, the IP also must not have an ABBA
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within any hypernet sequences, which are contained by square brackets.
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For example:
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• abba[mnop]qrst supports TLS (abba outside square brackets).
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• abcd[bddb]xyyx does not support TLS (bddb is within square brackets, even though xyyx is outside square brackets).
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• aaaa[qwer]tyui does not support TLS (aaaa is invalid; the interior characters must be different).
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• ioxxoj[asdfgh]zxcvbn supports TLS (oxxo is outside square brackets, even though it's within a larger string).
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How many IPs in your puzzle input support TLS?
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Your puzzle answer was _____.
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--- Part Two ---
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You would also like to know which IPs support SSL (super-secret listening).
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An IP supports SSL if it has an Area-Broadcast Accessor, or ABA, anywhere in the supernet sequences (outside any square bracketed sections),
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and a corresponding Byte Allocation Block, or BAB, anywhere in the hypernet sequences. An ABA is any three-character sequence which consists
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of the same character twice with a different character between them, such as xyx or aba. A corresponding BAB is the same characters but in
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reversed positions: yxy and bab, respectively.
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For example:
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• aba[bab]xyz supports SSL (aba outside square brackets with corresponding bab within square brackets).
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• xyx[xyx]xyx does not support SSL (xyx, but no corresponding yxy).
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• aaa[kek]eke supports SSL (eke in supernet with corresponding kek in hypernet; the aaa sequence is not related, because the interior
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character must be different).
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• zazbz[bzb]cdb supports SSL (zaz has no corresponding aza, but zbz has a corresponding bzb, even though zaz and zbz overlap).
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How many IPs in your puzzle input support SSL?
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Your puzzle answer was _______.
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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/2016/about
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. http://adventofcode.com/2016/support
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. http://adventofcode.com/2016/events
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. http://adventofcode.com/2016/settings
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. http://adventofcode.com/2016/auth/logout
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. http://adventofcode.com/2016
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. http://adventofcode.com/2016
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. http://adventofcode.com/2016/leaderboard
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. http://adventofcode.com/2016/stats
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. http://adventofcode.com/2016/sponsors
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. http://adventofcode.com/2016/sponsors
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. https://en.wikipedia.org/wiki/IP_address
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. https://en.wikipedia.org/wiki/IPv6
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. http://adventofcode.com/2016
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. http://adventofcode.com/2016/day/7/input
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