day07.html

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  15 Oh, hello!  Funny seeing you here.
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  17 I appreciate your enthusiasm, but you aren't going to find much down here.
  18 There certainly aren't clues to any of the puzzles.  The best surprises don't
  19 even appear in the source until you unlock them for real.
  20
  21 Please be careful with automated requests; I'm not Google, and I can only take
  22 so much traffic.  Please be considerate so that everyone gets to play.
  23
  24 If you're curious about how Advent of Code works, it's running on some custom
  25 Perl code. Other than a few integrations (auth, analytics, ads, social media),
  26 I built the whole thing myself, including the design, animations, prose, and
  27 all of the puzzles.
  28
  29 The puzzles probably took the longest; the easiest ones were around 45 minutes
  30 each, but the harder ones took 2-3 hours, and a few even longer than that. A
  31 lot of effort went into building this thing - I hope you're enjoying playing it
  32 as much as I enjoyed making it for you!
  33
  34 If you'd like to hang out, I'm @ericwastl on Twitter.
  35
  36 - Eric Wastl
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  88 <body>
  89 <header><div><h1 class="title-global"><a href="/">Advent of Code</a></h1><nav><ul><li><a href="/2016/about">[About]</a></li><li><a href="/2016/support">[AoC++]</a></li><li><a href="/2016/events">[Events]</a></li><li><a href="/2016/settings">[Settings]</a></li><li><a href="/2016/auth/logout">[Log Out]</a></li></ul></nav><div class="user">Neil Smith <span class="supporter">(AoC++)</span> <span class="star-count">14*</span></div></div><div><h1 class="title-event">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="title-event-wrap">/^</span><a href="/2016">2016</a><span class="title-event-wrap">$/</span></h1><nav><ul><li><a href="/2016">[Calendar]</a></li><li><a href="/2016/leaderboard">[Leaderboard]</a></li><li><a href="/2016/stats">[Stats]</a></li><li><a href="/2016/sponsors">[Sponsors]</a></li></ul></nav></div></header>
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 107 <article class="day-desc"><h2>--- Day 7: Internet Protocol Version 7 ---</h2><p>While snooping around the local network of EBHQ, you compile a list of <a href="https://en.wikipedia.org/wiki/IP_address">IP addresses</a> (they're IPv7, of course; <a href="https://en.wikipedia.org/wiki/IPv6">IPv6</a> is much too limited). You'd like to figure out which IPs support <em>TLS</em> (transport-layer snooping).</p>
 108 <p>An IP supports TLS if it has an Autonomous Bridge Bypass Annotation, or <span title="Any similarity to the pattern it describes is purely coincidental."><em>ABBA</em></span>.  An ABBA is any four-character sequence which consists of a pair of two different characters followed by the reverse of that pair, such as <code>xyyx</code> or <code>abba</code>.  However, the IP also must not have an ABBA within any hypernet sequences, which are contained by <em>square brackets</em>.</p>
 109 <p>For example:</p>
 110 <ul>
 111 <li><code>abba[mnop]qrst</code> supports TLS (<code>abba</code> outside square brackets).</li>
 112 <li><code>abcd[bddb]xyyx</code> does <em>not</em> support TLS (<code>bddb</code> is within square brackets, even though <code>xyyx</code> is outside square brackets).</li>
 113 <li><code>aaaa[qwer]tyui</code> does <em>not</em> support TLS (<code>aaaa</code> is invalid; the interior characters must be different).</li>
 114 <li><code>ioxxoj[asdfgh]zxcvbn</code> supports TLS (<code>oxxo</code> is outside square brackets, even though it's within a larger string).</li>
 115 </ul>
 116 <p><em>How many IPs</em> in your puzzle input support TLS?</p>
 117 </article>
 118 <p>Your puzzle answer was <code>105</code>.</p><article class="day-desc"><h2>--- Part Two ---</h2><p>You would also like to know which IPs support <em>SSL</em> (super-secret listening).</p>
 119 <p>An IP supports SSL if it has an Area-Broadcast Accessor, or <em>ABA</em>, anywhere in the supernet sequences (outside any square bracketed sections), and a corresponding Byte Allocation Block, or <em>BAB</em>, anywhere in the hypernet sequences. An ABA is any three-character sequence which consists of the same character twice with a different character between them, such as <code>xyx</code> or <code>aba</code>. A corresponding BAB is the same characters but in reversed positions: <code>yxy</code> and <code>bab</code>, respectively.</p>
 120 <p>For example:</p>
 121 <ul>
 122 <li><code>aba[bab]xyz</code> supports SSL (<code>aba</code> outside square brackets with corresponding <code>bab</code> within square brackets).</li>
 123 <li><code>xyx[xyx]xyx</code> does <em>not</em> support SSL (<code>xyx</code>, but no corresponding <code>yxy</code>).</li>
 124 <li><code>aaa[kek]eke</code> supports SSL (<code>eke</code> in supernet with corresponding <code>kek</code> in hypernet; the <code>aaa</code> sequence is not related, because the interior character must be different).</li>
 125 <li><code>zazbz[bzb]cdb</code> supports SSL (<code>zaz</code> has no corresponding <code>aza</code>, but <code>zbz</code> has a corresponding <code>bzb</code>, even though <code>zaz</code> and <code>zbz</code> overlap).</li>
 126 </ul>
 127 <p><em>How many IPs</em> in your puzzle input support SSL?</p>
 128 </article>
 129 <p>Your puzzle answer was <code>258</code>.</p><p class="day-success">Both parts of this puzzle are complete! They provide two gold stars: **</p>
 130 <p>At this point, you should <a href="/2016">return to your advent calendar</a> and try another puzzle.</p>
 131 <p>If you still want to see it, you can <a href="7/input" target="_blank">get your puzzle input</a>.</p>
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