Educational Codeforces Round 77 [Rated for Div. 2]
Difference between en4 and en5, changed 2,513 character(s)
Hello Codeforces!↵

On [contest_time:1260] [contest:1260] will start.↵

Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.net/blog/entry/51208">blog post</a>.↵
 ↵
This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.↵
 ↵
You will be given **6 problems** and **2 hours** to solve them.↵
 ↵
The problems were invented and prepared by ZiXuan Yan [user:RDDCCD,2019-11-26], Roman [user:Roms,2019-11-26] Glazov, Adilbek [user:adedalic,2019-11-26] Dalabaev, Vladimir [user:Vovuh,2019-11-26] Petrov, Ivan [user:BledDest,2019-11-26] Androsov, Maksim [user:Ne0n25,2019-11-26] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2019-11-26] Mirzayanov for great systems Polygon and Codeforces.↵

Good luck to all the participants!↵

Our friends at Harbour.Space also have a message for you:↵

_Hello Codeforces!_↵

_This week we have two new blog posts and a reminder of our Data Science Scholarship!_ ↵

**BLOG:** ↵

- [5 Reasons Why Interdisciplinary Learning Is Key](https://harbour.space/about/interdisciplinary-learning?utm_source=codeforces&utm_medium=partners)↵

- [Your Dream Job Doesn't Exist Today, And Here's Why](https://harbour.space/about/dream-job?utm_source=codeforces&utm_medium=partners)↵

**OUR SCHOLARSHIP**↵

_We are offering **fully-funded international scholarships** for exceptional tech specialists from around the world. Accelerate your career by becoming an industry expert capable of making key data-driven decisions that add value and drive innovation within tech industries._↵

_**Harbour.Space University** has partnered with **SCG**, a leading business conglomerate in the ASEAN region, to offer exceptional tech specialists the opportunity to work and study in two of the most dynamic and vibrant cities in the world. **Join our progressive two-year program based in Bangkok, with 6 of the 24 months in Barcelona**, to develop the international mindset needed to accelerate your career and redefine how data drives the businesses of the future._↵


<img alt="Codeforces and Harbour.Space" src="https://codeforces.net/predownloaded/76/9b/769b9154e0cda3f7c3be54e92a75ad1ff34e34ab.png" style="float:right;height: 265px; margin: 10px; max-width:50%;"/>↵

**Tuition fee:**↵

_2 years | €45,800_↵
 ↵
**Education:**↵

_3 hours of study per day  | 15h per week_ ↵

**Work Experience:**↵

_4 hours of internship per day at SCG | 20h per week_↵

**Living Allowance:**↵

_€16,800 euros | €700 per month living allowance_↵

<br>↵

<center style="margin:2.5em;">↵
<a href="https://in.harbour.space/bangkok-data-science-scholarship/?utm_source=codeforces&utm_medium=partners" style="text-decoration:none; font-size:18px; background-color:#523996; color:white; font-weight:bold; padding:0.5em 1em;">APPLY HERE&rarr;</a>↵
</center>↵

Congratulations to the winners:↵
<table class='bordertable'>↵
<tbody>↵
<tr>↵
<th>Rank</th>↵
<th>Competitor</th>↵
<th>Problems Solved</th>↵
<th>Penalty</th>↵
</tr>↵
<tr>↵
<td>1</td>↵
<td>[user:twitch.tv_wookje, 2019-11-27]</td>↵
<td>6</td>↵
<td>209</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:Tweetuzkokodayo, 2019-11-27]</td>↵
<td>6</td>↵
<td>219</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:socketnaut, 2019-11-27]</td>↵
<td>6</td>↵
<td>220</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:mango_lassi, 2019-11-27]</td>↵
<td>6</td>↵
<td>280</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:LJFOO7, 2019-11-27]</td>↵
<td>6</td>↵
<td>288</td>↵
</tr>↵
</tbody>↵
</table>↵


Congratulations to the best hackers:↵
<table class='bordertable'>↵
<tbody>↵
<tr>↵
<th>Rank</th>↵
<th>Competitor</th>↵
<th>Hack Count</th>↵
</tr>↵
<tr>↵
<td>1</td>↵
<td>[user:Rian_5900, 2019-11-27]</td>↵
<td><b><font color="green">60</font></b><b>:<font color="red">-3</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:blaction, 2019-11-27]</td>↵
<td><b><font color="green">13</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:Fyodor, 2019-11-27]</td>↵
<td><b><font color="green">14</font></b><b>:<font color="red">-5</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:Wolfy626, 2019-11-27]</td>↵
<td><b><font color="green">11</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:bmm, 2019-11-27]</td>↵
<td><b><font color="green">11</font></b><b>:<font color="red">-2</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
216 successful hacks and 246 unsuccessful hacks were made in total!↵

And finally people who were the first to solve each problem:↵
<table class='bordertable'>↵
<tbody>↵
<tr>↵
<th>Problem</th>↵
<th>Competitor</th>↵
<th>Penalty</th>↵
</tr>↵
<tr>↵
<td>A</td>↵
<td>[user:dorijanlendvaj, 2019-11-27]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:dorijanlendvaj, 2019-11-27]</td>↵
<td>0:02</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:dorijanlendvaj, 2019-11-27]</td>↵
<td>0:07</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:lzoi.win, 2019-11-27]</td>↵
<td>0:19</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:PinkRabbit, 2019-11-27]</td>↵
<td>0:16</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:_Kuroni_, 2019-11-27]</td>↵
<td>1:19</td>↵
</tr>↵
</tbody>↵
</table>↵

**UPD:** [Editorial is out](http://codeforces.net/blog/entry/71805)

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en5 English awoo 2019-11-28 19:29:45 2513
ru6 Russian awoo 2019-11-28 19:29:11 2487
en4 English awoo 2019-11-28 19:20:27 70
ru5 Russian awoo 2019-11-28 19:18:17 74
ru4 Russian Una_Shem 2019-11-26 18:13:49 29
ru3 Russian Una_Shem 2019-11-26 18:10:39 2090 (опубликовано)
en3 English Una_Shem 2019-11-26 17:34:57 2039 (published)
en2 English awoo 2019-11-26 16:06:32 37 Tiny change: 'epared by Roman [us' -> 'epared by ZiXuan Yan [user:RDDCCD], Roman [us'
ru2 Russian awoo 2019-11-26 16:06:13 37 Мелкая правка: ' готовили Роман [us' -> ' готовили ZiXuan Yan [user:RDDCCD], Роман [us'
en1 English awoo 2019-11-26 15:54:14 1280 Initial revision for English translation (saved to drafts)
ru1 Russian awoo 2019-11-26 15:53:34 1396 Первая редакция (сохранено в черновиках)