Educational Codeforces Round 86 [Rated for Div. 2]
Difference between en5 and en6, changed 2,571 character(s)
Hello Codeforces!↵

On [contest_time:1342] [contest:1342] 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.me/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 or 7 problems** and **2 hours** to solve them.↵
 ↵
The problems were invented and prepared by Roman [user:Roms,2020-04-25] Glazov, Adilbek [user:adedalic,2020-04-25] Dalabaev, Vladimir [user:vovuh,2020-04-25] Petrov, Ivan [user:BledDest,2020-04-25] Androsov, Maksim [user:Ne0n25,2020-04-25] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2020-04-25] Mirzayanov for great systems Polygon and Codeforces.↵

Special thanks to Mikhail [user:darnley,2020-04-26] Dvorkin for helping in round preparation!↵

Good luck to all the participants!↵

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

<img alt="Codeforces and Harbour.Space" src="https://codeforces.me/predownloaded/82/52/8252d924368cf9ef08db715a08861eaea55e12b2.png" style="float:center;height: 250px; margin: 10px; max-width:50%;"/>↵

_Hi Codeforces!_ ↵

_You really went for it in the last Educational Round! We had an all-time high participation of 21750 people :) We are happy to support such an awesome community, and look forward to growing these numbers in the future!_ ↵

_We are searching for diamonds in the rough &mdash; driven, talented humans, passionate about technology and design, undefined by nationality, gender and cultural background. We know that no diamond is born polished, so our mission is to identify and support as many talented young individuals as we can, so that they can fulfill their potential and secure the future they deserve._ ↵

_If you are graduating or have already completed a bachelor's degree, we are waiting for your applications for fully-funded Master's degree scholarships by the link below._↵

<center style="margin:2.5em;">↵
<a href="https://in.harbour.space/bangkok-scholarships/?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 NOW&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:DreamLolita, 2020-04-26]</td>↵
<td>6</td>↵
<td>211</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:KrK, 2020-04-26]</td>↵
<td>6</td>↵
<td>235</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:Heltion, 2020-04-26]</td>↵
<td>6</td>↵
<td>259</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:krijgertje, 2020-04-26]</td>↵
<td>6</td>↵
<td>268</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:Temotoloraia, 2020-04-26]</td>↵
<td>6</td>↵
<td>272</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:liouzhou_101, 2020-04-26]</td>↵
<td><b><font color="green">81</font></b><b>:<font color="red">-35</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:j_peters, 2020-04-26]</td>↵
<td><b><font color="green">29</font></b><b>:<font color="red">-16</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:eR6, 2020-04-26]</td>↵
<td><b><font color="green">18</font></b><b>:<font color="red">-19</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:tonyli00000, 2020-04-26]</td>↵
<td><b><font color="green">14</font></b><b>:<font color="red">-15</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:lollihunter, 2020-04-26]</td>↵
<td><b><font color="green">8</font></b><b>:<font color="red">-7</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
281 successful hacks and 925 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:Sevlll, 2020-04-26]</td>↵
<td>0:00</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:This0is0the0AmShZ, 2020-04-26]</td>↵
<td>0:02</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:DreamLolita, 2020-04-26]</td>↵
<td>0:03</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:xb0nS, 2020-04-26]</td>↵
<td>0:14</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:P.Alizadeh, 2020-04-26]</td>↵
<td>0:17</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:chemthan, 2020-04-26]</td>↵
<td>1:07</td>↵
</tr>↵
</tbody>↵
</table>↵

**UPD:** [Editorial is out](https://codeforces.me/blog/entry/76633)

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en6 English awoo 2020-04-27 17:51:40 2571
ru7 Russian awoo 2020-04-27 17:51:20 2547
en5 English awoo 2020-04-27 17:49:04 72
ru6 Russian awoo 2020-04-27 17:48:45 74
en4 English awoo 2020-04-26 17:07:30 97
ru5 Russian awoo 2020-04-26 17:06:03 95
ru4 Russian Una_Shem 2020-04-26 17:04:59 1 Мелкая правка: 'ий!\n\nТак же от наши' -> 'ий!\n\nТакже от наши'
ru3 Russian Una_Shem 2020-04-25 19:34:10 1407
en3 English Una_Shem 2020-04-25 17:59:18 0 (published)
ru2 Russian Una_Shem 2020-04-25 17:59:02 0 (опубликовано)
en2 English Una_Shem 2020-04-25 17:58:37 1362
en1 English awoo 2020-04-25 15:54:18 1285 Initial revision for English translation (saved to drafts)
ru1 Russian awoo 2020-04-25 15:53:37 1402 Первая редакция (сохранено в черновиках)