Educational Codeforces Round 105 [Rated for Div. 2]
Difference between en3 and en4, changed 2,452 character(s)
Hello Codeforces!↵

On [contest_time:1494] [contest:1494] 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://mirror.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,2021-03-01] Glazov, Adilbek [user:adedalic,2021-03-01] Dalabaev, Vladimir [user:vovuh,2021-03-01] Petrov, Ivan [user:BledDest,2021-03-01] Androsov, Maksim [user:Neon,2021-03-01] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2021-03-01] 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://mirror.codeforces.com/predownloaded/5a/65/5a654878acefd3f76ab65fe28a2314d5c372b31f.png" style="float:center; margin: 10px; max-width:50%;"/>↵

_Amazing news once again, Codeforces!_↵

_We are especially glad to have a chance to share our **scholarship opportunities** more often!_ ↵

_This time we have partnered with OneRagtime again to open the door for an exciting career in technology for the most talented people in our network._ ↵

_In partnership with OneRagtime, we are offering a full scholarship to study a Master’s in Computer Science at Harbour.Space while working as a [Full Stack Developer](https://harbour.space/scholarships/computer-science-apprenticeship-oneragtime?utm_source=codeforces&utm_medium=referral&utm_campaign=oneragtime-fullstack&utm_content=) at OneRagtime!_↵

_Scholarship Highlights:_↵

➡ _Work in Europe’s most exciting tech cities_↵

➡ _Scholarship value of up to €31,500_↵

➡ _Competitive compensation for the internship at OneRagtime (€800 / month)_↵

➡ _Opportunity to join OneRagtime full-time after graduation_↵

_Some of the advantages of working at OneRagtime:_↵

- _International team_↵
- _Fast-paced workplace_↵
- _Be a part of the OneRagtime adventure!_↵
- _Be fully immersed in the European tech ecosystem_↵
- _Thrive within a Venture Capital that does things a little differently_↵
- _Work in Europe’s most exciting tech cities_↵

<img alt="Codeforces and Harbour.Space" src="https://mirror.codeforces.com/predownloaded/cc/1a/cc1ae51debac520299c73933ab0f87bedc4c2dff.png" style="float:center; margin: 10px; max-width:50%;"/>↵


_We have previously partnered with other companies like OneRagtime, Hansgrohe, Coherra, and Remy Robotics to empower young talents around the world and help them boost their tech career. We’ve already filled a few of the positions with OneRagtime including:_↵

- _Full Stack Developer at **OneRagtime** awarded to Alejandro Martinez from Mexico_ ↵
- _UI/UX designer at **OneRagtime** awarded to [Davit Petriashvili](https://youtu.be/9s7vrYXUNwo) from Georgia_↵


_We are always happy to see Codeforces members join the Harbour.Space family. Apply now to get a chance to learn from the best in the field and kickstart your career!_↵

_Keep in touch and follow us on [LinkedIn](https://www.linkedin.com/school/harbour-space/) for more scholarship opportunities. And follow us on [Instagram](https://www.instagram.com/harbour.space/) to evidence student life, events, and success stories from our apprenticeship program students._↵

_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:antontrygubO_o, 2021-03-02]</td>↵
<td>6</td>↵
<td>251</td>↵
</tr>↵
<tr>↵
<td>1</td>↵
<td>[user:Pyqe, 2021-03-02]</td>↵
<td>6</td>↵
<td>251</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:kefaa2, 2021-03-02]</td>↵
<td>6</td>↵
<td>260</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:tute7627, 2021-03-02]</td>↵
<td>6</td>↵
<td>272</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:Um_nik, 2021-03-02]</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:noimi, 2021-03-02]</td>↵
<td><b><font color="green">11</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:abdallahmontaser, 2021-03-02]</td>↵
<td><b><font color="green">7</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:Origenes, 2021-03-02]</td>↵
<td><b><font color="green">6</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:Kregor, 2021-03-02]</td>↵
<td><b><font color="green">5</font></b><b>:<font color="red">-2</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:chilliagon, 2021-03-02]</td>↵
<td><b><font color="green">5</font></b><b>:<font color="red">-4</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
94 successful hacks and 293 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:noimi, 2021-03-02]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:noimi, 2021-03-02]</td>↵
<td>0:04</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:wygzgyw, 2021-03-02]</td>↵
<td>0:15</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:conan1412yang99, 2021-03-02]</td>↵
<td>0:16</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:thenymphsofdelphi, 2021-03-02]</td>↵
<td>0:15</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:rainboy, 2021-03-02]</td>↵
<td>0:35</td>↵
</tr>↵
</tbody>↵
</table>↵

**UPD:** [Editorial is out](https://mirror.codeforces.com/blog/entry/88344)

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en5 English awoo 2021-03-03 18:48:06 16 Tiny change: '<td>[user:abdallahmontaser, 2021-03-' -> '<td>[user:neal, 2021-03-'
en4 English awoo 2021-03-03 18:16:29 2452
ru5 Russian awoo 2021-03-03 18:15:24 2416
en3 English awoo 2021-03-03 16:16:21 70
ru4 Russian awoo 2021-03-03 16:15:57 74
ru3 Russian Una_Shem 2021-03-01 20:22:28 2711
en2 English Una_Shem 2021-03-01 20:09:19 2709 (published)
ru2 Russian Una_Shem 2021-03-01 20:07:58 0 (опубликовано)
en1 English awoo 2021-03-01 16:12:36 1284 Initial revision for English translation (saved to drafts)
ru1 Russian awoo 2021-03-01 16:11:45 1400 Первая редакция (сохранено в черновиках)