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+<title>Day 23 - Advent of Code 2017</title>
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+Oh, hello! Funny seeing you here.
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+I appreciate your enthusiasm, but you aren't going to find much down here.
+There certainly aren't clues to any of the puzzles. The best surprises don't
+even appear in the source until you unlock them for real.
+
+Please be careful with automated requests; I'm not Google, and I can only take
+so much traffic. Please be considerate so that everyone gets to play.
+
+If you're curious about how Advent of Code works, it's running on some custom
+Perl code. Other than a few integrations (auth, analytics, ads, social media),
+I built the whole thing myself, including the design, animations, prose, and
+all of the puzzles.
+
+The puzzles probably took the longest; the easiest ones took an hour or two
+each, but the harder ones took 4-5 hours, and a few even longer than that. A
+lot of effort went into building this thing - I hope you're enjoying playing it
+as much as I enjoyed making it for you!
+
+If you'd like to hang out, I'm @ericwastl on Twitter.
+
+- Eric Wastl
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+<header><div><h1 class="title-global"><a href="/">Advent of Code</a></h1><nav><ul><li><a href="/2017/about">[About]</a></li><li><a href="/2017/support">[AoC++]</a></li><li><a href="/2017/events">[Events]</a></li><li><a href="/2017/settings">[Settings]</a></li><li><a href="/2017/auth/logout">[Log Out]</a></li></ul></nav><div class="user">Neil Smith <span class="supporter">(AoC++)</span> <span class="star-count">46*</span></div></div><div><h1 class="title-event"> <span class="title-event-wrap">var y=</span><a href="/2017">2017</a><span class="title-event-wrap">;</span></h1><nav><ul><li><a href="/2017">[Calendar]</a></li><li><a href="/2017/leaderboard">[Leaderboard]</a></li><li><a href="/2017/stats">[Stats]</a></li><li><a href="/2017/sponsors">[Sponsors]</a></li></ul></nav></div></header>
+
+<div id="sidebar">
+<div id="sponsor"><div class="quiet">Our <a href="/2017/sponsors">sponsors</a> help make Advent of Code possible:</div><p><a href="http://kx.com/" target="_blank" onclick="if(ga)ga('send','event','sponsor','click',this.href);" rel="noopener">Kx Systems</a> - kdb+, the in-memory time series technology standard</p></div>
+<p class="quiet">By popular demand, there are now AoC-themed objects available (until Jan. 3rd)! Get them shipped <a href="https://teespring.com/advent-of-code" target="_blank">from the US</a> or <a href="https://teespring.com/advent-of-code-eu" target="_blank">from Europe</a>.</p>
+
+</div><!--/sidebar-->
+
+<main>
+<article class="day-desc"><h2>--- Day 23: Coprocessor Conflagration ---</h2><p>You decide to head directly to the CPU and fix the printer from there. As you get close, you find an <em>experimental coprocessor</em> doing so much work that the local programs are afraid it will <a href="https://en.wikipedia.org/wiki/Halt_and_Catch_Fire">halt and catch fire</a>. This would cause serious issues for the rest of the computer, so you head in and see what you can do.</p>
+<p>The code it's running seems to be a variant of the kind you saw recently on that <a href="18">tablet</a>. The general functionality seems <em>very similar</em>, but some of the instructions are different:</p>
+<ul>
+<li><code>set X Y</code> <em>sets</em> register <code>X</code> to the value of <code>Y</code>.</li>
+<li><code>sub X Y</code> <em>decreases</em> register <code>X</code> by the value of <code>Y</code>.</li>
+<li><code>mul X Y</code> sets register <code>X</code> to the result of <em>multiplying</em> the value contained in register <code>X</code> by the value of <code>Y</code>.</li>
+<li><code>jnz X Y</code> <em>jumps</em> with an offset of the value of <code>Y</code>, but only if the value of <code>X</code> is <em>not zero</em>. (An offset of <code>2</code> skips the next instruction, an offset of <code>-1</code> jumps to the previous instruction, and so on.)</li>
+<p>Only the instructions listed above are used. The eight registers here, named <code>a</code> through <code>h</code>, all start at <code>0</code>.</p>
+</ul>
+<p>The coprocessor is currently set to some kind of <em>debug mode</em>, which allows for testing, but prevents it from doing any meaningful work.</p>
+<p>If you run the program (your puzzle input), <em>how many times is the <code>mul</code> instruction invoked?</em></p>
+</article>
+<p>Your puzzle answer was <code>6724</code>.</p><article class="day-desc"><h2>--- Part Two ---</h2><p>Now, it's time to fix the problem.</p>
+<p>The <em>debug mode switch</em> is wired directly to register <code>a</code>. You <span title="From 'magic' to 'more magic'.">flip the switch</span>, which makes <em>register <code>a</code> now start at <code>1</code></em> when the program is executed.</p>
+<p>Immediately, the coprocessor begins to overheat. Whoever wrote this program obviously didn't choose a very efficient implementation. You'll need to <em>optimize the program</em> if it has any hope of completing before Santa needs that printer working.</p>
+<p>The coprocessor's ultimate goal is to determine the final value left in register <code>h</code> once the program completes. Technically, if it had that... it wouldn't even need to run the program.</p>
+<p>After setting register <code>a</code> to <code>1</code>, if the program were to run to completion, <em>what value would be left in register <code>h</code>?</em></p>
+</article>
+<p>Your puzzle answer was <code>903</code>.</p><p class="day-success">Both parts of this puzzle are complete! They provide two gold stars: **</p>
+<p>At this point, you should <a href="/2017">return to your advent calendar</a> and try another puzzle.</p>
+<p>If you still want to see it, you can <a href="23/input" target="_blank">get your puzzle input</a>.</p>
+<p>You can also <span class="share">[Share<span class="share-content">on
+ <a href="https://twitter.com/intent/tweet?text=I%27ve+completed+%22Coprocessor+Conflagration%22+%2D+Day+23+%2D+Advent+of+Code+2017&url=http%3A%2F%2Fadventofcode%2Ecom%2F2017%2Fday%2F23&related=ericwastl&hashtags=AdventOfCode" target="_blank">Twitter</a>
+ <a href="https://plus.google.com/share?url=http%3A%2F%2Fadventofcode%2Ecom%2F2017%2Fday%2F23" target="_blank">Google+</a>
+ <a href="http://www.reddit.com/submit?url=http%3A%2F%2Fadventofcode%2Ecom%2F2017%2Fday%2F23&title=I%27ve+completed+%22Coprocessor+Conflagration%22+%2D+Day+23+%2D+Advent+of+Code+2017" target="_blank">Reddit</a
+></span>]</span> this puzzle.</p>
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