Educational Codeforces Round 88 [Rated for Div. 2]
Difference between en3 and en4, changed 2,535 character(s)
Hello Codeforces!↵

On [contest_time:1359] [contest:1359] 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 or 7 problems** and **2 hours** to solve them.↵
 ↵
The problems were invented and prepared by Roman [user:Roms,2020-05-27] Glazov, Adilbek [user:adedalic,2020-05-27] Dalabaev, Vladimir [user:vovuh,2020-05-27] Petrov, Ivan [user:BledDest,2020-05-27] Androsov, Maksim [user:Ne0n25,2020-05-27] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2020-05-27] Mirzayanov for great systems Polygon and Codeforces.↵

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.net/predownloaded/2d/74/2d74b3338febcfcef9947313492d0578cbe8b386.png" style="float:center;height: 350px; margin: 10px; max-width:50%;"/>↵

_Hey Codeforces!_ ↵

_As you may remember, we have a free webinar series starring our all-star faculty members who share valuable content and insiders’ knowledge that you don’t get to learn about in traditional classrooms._↵

_Join us tomorrow, Thursday, May 28 at 12h (BCN) / 17h (BKK) to watch Sergey Gordeychik, CIO of the Inception Institute of Artificial Intelligence, share his expertise and insights in his “Digital Lockdown: AI against COVID-19” session. Sergey will discuss how AI is being used both positively and negatively during the COVID-19 global pandemic._ ↵
_Tune in for some practical examples of how companies are using AI to innovate and disrupt during a time of crisis, exploring topics like Medical Imaging for CT analysis, diagnosis and mass surveillance._↵

_By participating in this webinar you will get a certificate of participation, a special digital gift from Sergey, and stand a chance to win a FREE 3-week module at Harbour.Space University depending on the availability and prerequisites of the course._ ↵

_See you tomorrow, and good luck on your round!_ ↵

<center style="margin:2.5em;">↵
<a href="https://bit.ly/2WBPu6L" style="text-decoration:none; font-size:16px; background-color:#523996; color:white; font-weight:bold; padding:0.5em 1em;">Reserve your spot now!</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:kefaa2, 2020-05-28]</td>↵
<td>6</td>↵
<td>174</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:bmerry, 2020-05-28]</td>↵
<td>6</td>↵
<td>219</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:dlalswp25, 2020-05-28]</td>↵
<td>6</td>↵
<td>233</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:hepth, 2020-05-28]</td>↵
<td>6</td>↵
<td>238</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:Volkov_Ivan, 2020-05-28]</td>↵
<td>6</td>↵
<td>251</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:Hideki_Ryuga_L, 2020-05-28]</td>↵
<td><b><font color="green">37</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:KonaeAkira, 2020-05-28]</td>↵
<td><b><font color="green">19</font></b><b>:<font color="red">-1</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:ujjwalsingh30, 2020-05-28]</td>↵
<td><b><font color="green">18</font></b><b>:<font color="red">-1</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:veteran_, 2020-05-28]</td>↵
<td><b><font color="green">14</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:hashlib, 2020-05-28]</td>↵
<td><b><font color="green">13</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
318 successful hacks and 469 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:andryusha_na_knopke, 2020-05-28]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:thech0sen1, 2020-05-28]</td>↵
<td>0:03</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:IAKWF, 2020-05-28]</td>↵
<td>0:11</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:Kerim.K, 2020-05-28]</td>↵
<td>0:06</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:HeHere, 2020-05-28]</td>↵
<td>0:06</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:user202729_, 2020-05-28]</td>↵
<td>0:44</td>↵
</tr>↵
</tbody>↵
</table>↵

**UPD:** [Editorial is out](https://codeforces.net/blog/entry/78116)

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en4 English awoo 2020-05-29 18:34:35 2535
ru5 Russian awoo 2020-05-29 18:33:55 2521
ru4 Russian Una_Shem 2020-05-27 20:11:33 1720
en3 English awoo 2020-05-27 19:15:47 39 Tiny change: 'start.\n\n**Please notice the unusual time.**\n\nSeries' -> 'start.\n\nSeries'
ru3 Russian awoo 2020-05-27 19:15:36 76
ru2 Russian Una_Shem 2020-05-27 19:06:54 0 (опубликовано)
en2 English Una_Shem 2020-05-27 19:06:32 1592 (published)
en1 English awoo 2020-05-27 15:51:53 1324 Initial revision for English translation (saved to drafts)
ru1 Russian awoo 2020-05-27 15:50:59 1477 Первая редакция (сохранено в черновиках)