advent-of-code-08.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.  You do risk spoiling a few
  19 surprises for yourself, though.  Best to play the normal way and discover
  20 everything as it was intended, I think.  The best surprises don't even appear
  21 in the source until you unlock them for real.
  22
  23 Please be careful with automated requests; I'm not Google, and I can only take
  24 so much traffic.  Please be considerate so that everyone gets to play.
  25
  26 If you're curious about how Advent of Code works, it's running on some custom
  27 Perl code. Other than a few integrations (auth, analytics, ads, social media),
  28 I built the whole thing myself, including the design, animations, prose, and
  29 all of the puzzles.
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  31 The puzzles probably took the longest; the easiest ones were around 45 minutes
  32 each, but the harder ones took 2-3 hours, some even longer than that. A lot of
  33 effort went into building this thing - I hope you're enjoying playing it as
  34 much as I enjoyed making it for you!
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  36 If you'd like to hang out, I'm @ericwastl on Twitter.
  37
  38 - Eric Wastl
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  89 -->
  90 <body>
  91 <header><h1><a href="/">Advent of Code</a></h1><div class="user">Neil Smith <span class="star-count">26*</span></div><nav><ul><li><a href="/about">[About]</a></li><li><a href="/stats">[Stats]</a></li><li><a href="/leaderboard">[Leaderboard]</a></li><li><a href="/settings">[Settings]</a></li><li><a href="/auth/logout">[Log out]</a></li></ul></nav></header>
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 106 <article class="day-desc"><h2>--- Day 8: Matchsticks ---</h2><p>Space on the sleigh is limited this year, and so Santa will be bringing his list as a digital copy. He needs to know how much space it will take up when stored.</p>
 107 <p>It is common in many programming languages to provide a way to <span title="It is common for many programmers to try to escape from string escaping.  No such luck here.">escape</span> special characters in strings.  For example, <a href="https://en.wikipedia.org/wiki/Escape_sequences_in_C">C</a>, <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String">JavaScript</a>, <a href="http://perldoc.perl.org/perlop.html#Quote-and-Quote-like-Operators">Perl</a>, <a href="https://docs.python.org/2.0/ref/strings.html">Python</a>, and even <a href="http://php.net/manual/en/language.types.string.php#language.types.string.syntax.double">PHP</a> handle special characters in very similar ways.</p>
 108 <p>However, it is important to realize the difference between the number of characters <em>in the code representation of the string literal</em> and the number of characters <em>in the in-memory string itself</em>.</p>
 109 <p>For example:</p>
 110 <ul>
 111 <li><code>""</code> is <code>2</code> characters of code (the two double quotes), but the string contains zero characters.</li>
 112 <li><code>"abc"</code> is <code>5</code> characters of code, but <code>3</code> characters in the string data.</li>
 113 <li><code>"aaa\"aaa"</code> is <code>10</code> characters of code, but the string itself contains six "a" characters and a single, escaped quote character, for a total of <code>7</code> characters in the string data.</li>
 114 <li><code>"\x27"</code> is <code>6</code> characters of code, but the string itself contains just one - an apostrophe (<code>'</code>), escaped using hexadecimal notation.</li>
 115 </ul>
 116 <p>Santa's list is a file that contains many double-quoted string literals, one on each line.  The only escape sequences used are <code>\\</code> (which represents a single backslash), <code>\"</code> (which represents a lone double-quote character), and <code>\x</code> plus two hexadecimal characters (which represents a single character with that ASCII code).</p>
 117 <p>Disregarding the whitespace in the file, what is <em>the number of characters of code for string literals</em> minus <em>the number of characters in memory for the values of the strings</em> in total for the entire file?</p>
 118 <p>For example, given the four strings above, the total number of characters of string code (<code>2 + 5 + 10 + 6 = 23</code>) minus the total number of characters in memory for string values (<code>0 + 3 + 7 + 1 = 11</code>) is <code>23 - 11 = 12</code>.</p>
 119 </article>
 120 <p>Your puzzle answer was <code>1350</code>.</p><article class="day-desc"><h2>--- Part Two ---</h2><p>Now, let's go the other way.  In addition to finding the number of characters of code, you should now <em>encode each code representation as a new string</em> and find the number of characters of the new encoded representation, including the surrounding double quotes.</p>
 121 <p>For example:</p>
 122 <ul>
 123 <li><code>""</code> encodes to <code>"\"\""</code>, an increase from <code>2</code> characters to <code>6</code>.</li>
 124 <li><code>"abc"</code> encodes to <code>"\"abc\""</code>, an increase from <code>5</code> characters to <code>9</code>.</li>
 125 <li><code>"aaa\"aaa"</code> encodes to <code>"\"aaa\\\"aaa\""</code>, an increase from <code>10</code> characters to <code>16</code>.</li>
 126 <li><code>"\x27"</code> encodes to <code>"\"\\x27\""</code>, an increase from <code>6</code> characters to <code>11</code>.</li>
 127 </ul>
 128 <p>Your task is to find <em>the total number of characters to represent the newly encoded strings</em> minus <em>the number of characters of code in each original string literal</em>. For example, for the strings above, the total encoded length (<code>6 + 9 + 16 + 11 = 42</code>) minus the characters in the original code representation (<code>23</code>, just like in the first part of this puzzle) is <code>42 - 23 = 19</code>.</p>
 129 </article>
 130 <p>Your puzzle answer was <code>2085</code>.</p><p class="day-success">Both parts of this puzzle are complete! They provide two gold stars: **</p>
 131 <p>At this point, you should <a href="/">return to your advent calendar</a> and try another puzzle.</p>
 132 <p>If you still want to see it, you can <a href="/day/8/input" target="_blank">get your puzzle input</a>.</p>
 133 <p>You can also <span class="share">[Share<span class="share-content">on
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 138  this puzzle.</p>
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