Educational Codeforces Round 100 [Rated for Div. 2]
Difference between en4 and en5, changed 2,585 character(s)
Hello Codeforces!↵

On [contest_time:1463] [contest:1463] 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,2020-12-16] Glazov, Adilbek [user:adedalic,2020-12-16] Dalabaev, Vladimir [user:vovuh,2020-12-16] Petrov, Ivan [user:BledDest,2020-12-16] Androsov, Maksim [user:Ne0n25,2020-12-16] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2020-12-16] Mirzayanov for great systems Polygon and Codeforces.↵

Also thanks to Nikolay [user:KAN,2020-12-17] Kalinin for one of the problems' ideas.↵

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.com/predownloaded/4d/30/4d302d046253a2b01c7dc593cf2a91cbd71d3974.png" style="float:left;height: 200px; margin: 10px; max-width:50%;"/>↵

_Hey Codeforces!_↵

_It’s almost the Holiday season, and this year, we have an extra reason to celebrate &mdash; this December marks Harbour.Space’s 5-year anniversary!_↵

_Looking back, we’re especially thankful for the wonderful partnerships that have made our university what it is today._ ↵

_Codeforces has been one of our key partners since the beginning, and we would like to thank the community for growing with us for the past 5 years._ ↵

_You guys are rock stars, and we’re excited to see where the future takes us both._ ↵

<p align="left">Best,↵
<br>↵
Harbour.Space University</p>


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:heno239, 2020-12-17]</td>↵
<td>6</td>↵
<td>174</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:Geothermal, 2020-12-17]</td>↵
<td>6</td>↵
<td>178</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:stevenkplus, 2020-12-17]</td>↵
<td>6</td>↵
<td>238</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:hank55663, 2020-12-17]</td>↵
<td>5</td>↵
<td>87</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:neal, 2020-12-17]</td>↵
<td>5</td>↵
<td>121</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:3.141592653, 2020-12-17]</td>↵
<td><b><font color="green">49</font></b><b>:<font color="red">-3</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:sheaf, 2020-12-17]</td>↵
<td><b><font color="green">48</font></b><b>:<font color="red">-17</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:adnan_toky, 2020-12-17]</td>↵
<td><b><font color="green">32</font></b><b>:<font color="red">-2</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:_Backl1ght, 2020-12-17]</td>↵
<td><b><font color="green">30</font></b><b>:<font color="red">-2</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:star_xingchen_c, 2020-12-17]</td>↵
<td><b><font color="green">27</font></b><b>:<font color="red">-1</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
1083 successful hacks and 1034 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:I_love_Anya_Prokopyeva, 2020-12-17]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:System_2020, 2020-12-17]</td>↵
<td>0:03</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:Geothermal, 2020-12-17]</td>↵
<td>0:11</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:peti1234, 2020-12-17]</td>↵
<td>0:06</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:CoderAnshu, 2020-12-17]</td>↵
<td>0:23</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:heno239, 2020-12-17]</td>↵
<td>1:13</td>↵
</tr>↵
</tbody>↵
</table>

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en6 English awoo 2020-12-18 18:26:52 72
ru5 Russian awoo 2020-12-18 18:26:30 74
en5 English awoo 2020-12-18 18:25:12 2585
ru4 Russian awoo 2020-12-18 18:24:57 2561
en4 English awoo 2020-12-17 15:29:00 88
ru3 Russian awoo 2020-12-17 15:27:50 95
en3 English Una_Shem 2020-12-16 17:45:11 7 Tiny change: 'le="float:right;height: ' -> 'le="float:left;height: '
ru2 Russian Una_Shem 2020-12-16 17:44:14 957 (опубликовано)
en2 English Una_Shem 2020-12-16 17:35:59 866 (published)
en1 English awoo 2020-12-16 11:06:06 1286 Initial revision for English translation (saved to drafts)
ru1 Russian awoo 2020-12-16 11:05:21 1402 Первая редакция (сохранено в черновиках)