problems/day01.html

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   5 <title>Day 1 - Advent of Code 2020</title>
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  16 Oh, hello!  Funny seeing you here.
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  18 I appreciate your enthusiasm, but you aren't going to find much down here.
  19 There certainly aren't clues to any of the puzzles.  The best surprises don't
  20 even appear in the source until you unlock them for real.
  21
  22 Please be careful with automated requests; I'm not a massive company, and I can
  23 only take so much traffic.  Please be considerate so that everyone gets to play.
  24
  25 If you're curious about how Advent of Code works, it's running on some custom
  26 Perl code. Other than a few integrations (auth, analytics, social media), I
  27 built the whole thing myself, including the design, animations, prose, and all
  28 of the puzzles.
  29
  30 The puzzles are most of the work; preparing a new calendar and a new set of
  31 puzzles each year takes all of my free time for 4-5 months. A lot of effort
  32 went into building this thing - I hope you're enjoying playing it as much as I
  33 enjoyed making it for you!
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  35 If you'd like to hang out, I'm @ericwastl on Twitter.
  36
  37 - Eric Wastl
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  89 <body>
  90 <header><div><h1 class="title-global"><a href="/">Advent of Code</a></h1><nav><ul><li><a href="/2020/about">[About]</a></li><li><a href="/2020/events">[Events]</a></li><li><a href="https://teespring.com/stores/advent-of-code" target="_blank">[Shop]</a></li><li><a href="/2020/settings">[Settings]</a></li><li><a href="/2020/auth/logout">[Log Out]</a></li></ul></nav><div class="user">Neil Smith <a href="/2020/support" class="supporter-badge" title="Advent of Code Supporter">(AoC++)</a> <span class="star-count">4*</span></div></div><div><h1 class="title-event">&nbsp;<span class="title-event-wrap">{&apos;year&apos;:</span><a href="/2020">2020</a><span class="title-event-wrap">}</span></h1><nav><ul><li><a href="/2020">[Calendar]</a></li><li><a href="/2020/support">[AoC++]</a></li><li><a href="/2020/sponsors">[Sponsors]</a></li><li><a href="/2020/leaderboard">[Leaderboard]</a></li><li><a href="/2020/stats">[Stats]</a></li></ul></nav></div></header>
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  93 <div id="sponsor"><div class="quiet">Our <a href="/2020/sponsors">sponsors</a> help make Advent of Code possible:</div><div class="sponsor"><a href="https://jobs.americanexpress.com/technology" target="_blank" onclick="if(ga)ga('send','event','sponsor','sidebar',this.href);" rel="noopener">American Express</a> - We architect, code and ship software that makes us an essential part of our customers’ digital lives. Work with the latest tech and back the engineering community through open source. Find your place in tech on #TeamAmex.</div></div>
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  98 <article class="day-desc"><h2>--- Day 1: Report Repair ---</h2><p>After saving Christmas <a href="/events">five years in a row</a>, you've decided to take a vacation at a nice resort on a tropical island. <span title="WHAT COULD GO WRONG">Surely</span>, Christmas will go on without you.</p>
  99 <p>The tropical island has its own currency and is entirely cash-only.  The gold coins used there have a little picture of a starfish; the locals just call them <em class="star">stars</em>. None of the currency exchanges seem to have heard of them, but somehow, you'll need to find fifty of these coins by the time you arrive so you can pay the deposit on your room.</p>
 100 <p>To save your vacation, you need to get all <em class="star">fifty stars</em> by December 25th.</p>
 101 <p>Collect stars by solving puzzles.  Two puzzles will be made available on each day in the Advent calendar; the second puzzle is unlocked when you complete the first.  Each puzzle grants <em class="star">one star</em>. Good luck!</p>
 102 <p>Before you leave, the Elves in accounting just need you to fix your <em>expense report</em> (your puzzle input); apparently, something isn't quite adding up.</p>
 103 <p>Specifically, they need you to <em>find the two entries that sum to <code>2020</code></em> and then multiply those two numbers together.</p>
 104 <p>For example, suppose your expense report contained the following:</p>
 105 <pre><code>1721
 106 979
 107 366
 108 299
 109 675
 110 1456
 111 </code></pre>
 112 <p>In this list, the two entries that sum to <code>2020</code> are <code>1721</code> and <code>299</code>. Multiplying them together produces <code>1721 * 299 = 514579</code>, so the correct answer is <code><em>514579</em></code>.</p>
 113 <p>Of course, your expense report is much larger. <em>Find the two entries that sum to <code>2020</code>; what do you get if you multiply them together?</em></p>
 114 </article>
 115 <p>Your puzzle answer was <code>982464</code>.</p><article class="day-desc"><h2 id="part2">--- Part Two ---</h2><p>The Elves in accounting are thankful for your help; one of them even offers you a starfish coin they had left over from a past vacation. They offer you a second one if you can find <em>three</em> numbers in your expense report that meet the same criteria.</p>
 116 <p>Using the above example again, the three entries that sum to <code>2020</code> are <code>979</code>, <code>366</code>, and <code>675</code>. Multiplying them together produces the answer, <code><em>241861950</em></code>.</p>
 117 <p>In your expense report, <em>what is the product of the three entries that sum to <code>2020</code>?</em></p>
 118 </article>
 119 <p>Your puzzle answer was <code>162292410</code>.</p><p class="day-success">Both parts of this puzzle are complete! They provide two gold stars: **</p>
 120 <p>At this point, you should <a href="/2020">return to your Advent calendar</a> and try another puzzle.</p>
 121 <p>If you still want to see it, you can <a href="1/input" target="_blank">get your puzzle input</a>.</p>
 122 <p>You can also <span class="share">[Share<span class="share-content">on
 123   <a href="https://twitter.com/intent/tweet?text=I%27ve+completed+%22Report+Repair%22+%2D+Day+1+%2D+Advent+of+Code+2020&amp;url=https%3A%2F%2Fadventofcode%2Ecom%2F2020%2Fday%2F1&amp;related=ericwastl&amp;hashtags=AdventOfCode" target="_blank">Twitter</a>
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 125 ></span>]</span> this puzzle.</p>
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