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+<title>Day 4 - Advent of Code 2019</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 a massive company, 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 are most of the work; preparing a new calendar and a new set of
+puzzles each year takes all of my free time for 4-5 months. 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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+-->
+<body>
+<header><div><h1 class="title-global"><a href="/">Advent of Code</a></h1><nav><ul><li><a href="/2019/about">[About]</a></li><li><a href="/2019/events">[Events]</a></li><li><a href="https://teespring.com/adventofcode-2019" target="_blank">[Shop]</a></li><li><a href="/2019/settings">[Settings]</a></li><li><a href="/2019/auth/logout">[Log Out]</a></li></ul></nav><div class="user">Neil Smith <a href="/2019/support" class="supporter-badge" title="Advent of Code Supporter">(AoC++)</a> <span class="star-count">8*</span></div></div><div><h1 class="title-event"> <span class="title-event-wrap">0x0000|</span><a href="/2019">2019</a><span class="title-event-wrap"></span></h1><nav><ul><li><a href="/2019">[Calendar]</a></li><li><a href="/2019/support">[AoC++]</a></li><li><a href="/2019/sponsors">[Sponsors]</a></li><li><a href="/2019/leaderboard">[Leaderboard]</a></li><li><a href="/2019/stats">[Stats]</a></li></ul></nav></div></header>
+
+<div id="sidebar">
+<div id="sponsor"><div class="quiet">Our <a href="/2019/sponsors">sponsors</a> help make Advent of Code possible:</div><div class="sponsor"><a href="https://www.twilio.com/quest" target="_blank" onclick="if(ga)ga('send','event','sponsor','sidebar',this.href);" rel="noopener">TwilioQuest</a> - Play Advent of Code and earn rad loot in TwilioQuest, a developer RPG for Mac, Windows, and Linux. Learn JavaScript, Python, git, APIs for SMS, VoIP, or WhatsApp, and much more.</div></div>
+</div><!--/sidebar-->
+
+<main>
+<article class="day-desc"><h2>--- Day 4: Secure Container ---</h2><p>You arrive at the Venus fuel depot only to discover it's protected by a password. The Elves had written the password on a sticky note, but someone <span title="Look on the bright side - isn't it more secure if nobody knows the password?">threw it out</span>.</p>
+<p>However, they do remember a few key facts about the password:</p>
+<ul>
+<li>It is a six-digit number.</li>
+<li>The value is within the range given in your puzzle input.</li>
+<li>Two adjacent digits are the same (like <code>22</code> in <code>1<em>22</em>345</code>).</li>
+<li>Going from left to right, the digits <em>never decrease</em>; they only ever increase or stay the same (like <code>111123</code> or <code>135679</code>).</li>
+</ul>
+<p>Other than the range rule, the following are true:</p>
+<ul>
+<li><code>111111</code> meets these criteria (double <code>11</code>, never decreases).</li>
+<li><code>2234<em>50</em></code> does not meet these criteria (decreasing pair of digits <code>50</code>).</li>
+<li><code>123789</code> does not meet these criteria (no double).</li>
+</ul>
+<p><em>How many different passwords</em> within the range given in your puzzle input meet these criteria?</p>
+</article>
+<p>Your puzzle answer was <code>1955</code>.</p><article class="day-desc"><h2 id="part2">--- Part Two ---</h2><p>An Elf just remembered one more important detail: the two adjacent matching digits <em>are not part of a larger group of matching digits</em>.</p>
+<p>Given this additional criterion, but still ignoring the range rule, the following are now true:</p>
+<ul>
+<li><code>112233</code> meets these criteria because the digits never decrease and all repeated digits are exactly two digits long.</li>
+<li><code>123<em>444</em></code> no longer meets the criteria (the repeated <code>44</code> is part of a larger group of <code>444</code>).</li>
+<li><code>111122</code> meets the criteria (even though <code>1</code> is repeated more than twice, it still contains a double <code>22</code>).</li>
+</ul>
+<p><em>How many different passwords</em> within the range given in your puzzle input meet all of the criteria?</p>
+</article>
+<p>Your puzzle answer was <code>1319</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="/2019">return to your Advent calendar</a> and try another puzzle.</p>
+<p>Your puzzle input was <code class="puzzle-input">134792-675810</code>.</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+%22Secure+Container%22+%2D+Day+4+%2D+Advent+of+Code+2019&url=https%3A%2F%2Fadventofcode%2Ecom%2F2019%2Fday%2F4&related=ericwastl&hashtags=AdventOfCode" target="_blank">Twitter</a>
+ <a href="javascript:void(0);" onclick="var mastodon_instance=prompt('Mastodon Instance / Server Name?'); if(typeof mastodon_instance==='string' && mastodon_instance.length){this.href='https://'+mastodon_instance+'/share?text=I%27ve+completed+%22Secure+Container%22+%2D+Day+4+%2D+Advent+of+Code+2019+https%3A%2F%2Fadventofcode%2Ecom%2F2019%2Fday%2F4'}else{return false;}" target="_blank">Mastodon</a
+></span>]</span> this puzzle.</p>
+</main>
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