Educational Codeforces Round 102 [Rated for Div. 2]
Difference between en6 and en7, changed 2,672 character(s)
Hello Codeforces!↵

On [contest_time:1473] [contest:1473] 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.com/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,2021-01-13] Glazov, Adilbek [user:adedalic,2021-01-13] Dalabaev, Vladimir [user:vovuh,2021-01-13] Petrov, Ivan [user:BledDest,2021-01-13] Androsov, Maksim [user:Neon,2021-01-13] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2021-01-13] Mirzayanov for great systems Polygon and Codeforces.↵

Good luck to all the participants!↵

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

_Hey Codeforces and Happy New Year!_↵

_To kick off 2021, we want to introduce you to new opportunities!_ ↵

_Undoubtedly, Harbour.Space is always happy to see Codeforces participants among our students! Young talents who are eager to learn, challenge themselves, seek continuous development are our top priority._ ↵

_That’s why we want to announce our amazing **apprenticeship program**._ ↵

_Our mission is to spark positive impact cycles between promising young talent, the tech industry, and innovative educators. We continuously work on finding the perfect match between talent and companies._ ↵

_Check out a success story from one of our first apprenticeship program students._ ↵

<iframe width="560" height="315" src="https://www.youtube.com/embed/9s7vrYXUNwo" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>↵

_David is a UX/UI specialist from Georgia who received a full scholarship from venture capital fund, OneRagtime._ ↵

_But there are plenty more apprenticeship opportunities coming in the fields of technology, entrepreneurship, and design. Interested? Keep in touch and follow us on [LinkedIn](https://www.linkedin.com/school/harbour-space/) for more fantastic opportunities._ ↵

_Good luck on your round, and see you next time!_↵

_Harbour.Space University_


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:jiangly, 2021-01-14]</td>↵
<td>7</td>↵
<td>201</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:hank55663, 2021-01-14]</td>↵
<td>7</td>↵
<td>210</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:BigBag, 2021-01-14]</td>↵
<td>7</td>↵
<td>282</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:Lawali, 2021-01-14]</td>↵
<td>7</td>↵
<td>283</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:FluffyT, 2021-01-14]</td>↵
<td>7</td>↵
<td>306</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:ariloc, 2021-01-14]</td>↵
<td><b><font color="green">35</font></b><b>:<font color="red">-1</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:smax, 2021-01-14]</td>↵
<td><b><font color="green">34</font></b><b>:<font color="red">-9</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:mrkarlo, 2021-01-14]</td>↵
<td><b><font color="green">27</font></b><b>:<font color="red">-5</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:VTifand, 2021-01-14]</td>↵
<td><b><font color="green">19</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:BlueGagosipda, 2021-01-14]</td>↵
<td><b><font color="green">21</font></b><b>:<font color="red">-22</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
242 successful hacks and 872 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:Geothermal, 2021-01-14]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:Geothermal, 2021-01-14]</td>↵
<td>0:02</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:SSRS_, 2021-01-14]</td>↵
<td>0:09</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:Alfalfa_w, 2021-01-14]</td>↵
<td>0:09</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:_FlyingColor_, 2021-01-14]</td>↵
<td>0:16</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:Apsara, 2021-01-14]</td>↵
<td>0:40</td>↵
</tr>↵
<tr>↵
<td>G</td>↵
<td>[user:tfg, 2021-01-14]</td>↵
<td>0:48</td>↵
</tr>↵
</tbody>↵
</table>↵

**UPD:** [Editorial is out](https://codeforces.com/blog/entry/86827)

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en7 English awoo 2021-01-15 17:58:40 2672
ru6 Russian awoo 2021-01-15 17:58:07 2650
ru5 Russian Una_Shem 2021-01-13 21:44:57 11
ru4 Russian Una_Shem 2021-01-13 20:05:37 62
ru3 Russian Una_Shem 2021-01-13 20:03:28 1483
en6 English Una_Shem 2021-01-13 18:10:38 29 Tiny change: 'ext time!_ ' -> 'ext time!_\n\n_Harbour.Space University_'
en5 English Una_Shem 2021-01-13 18:07:43 0 (published)
en4 English Una_Shem 2021-01-13 18:07:22 4 (saved to drafts)
ru2 Russian Una_Shem 2021-01-13 18:06:19 0 (опубликовано)
en3 English Una_Shem 2021-01-13 18:03:29 4
en2 English Una_Shem 2021-01-13 18:02:34 1410 (published)
en1 English awoo 2021-01-13 14:18:07 1284 Initial revision for English translation (saved to drafts)
ru1 Russian awoo 2021-01-13 14:17:11 1400 Первая редакция (сохранено в черновиках)