Educational Codeforces Round 31
Difference between en1 and en2, changed 2,462 character(s)
Hello Codeforces!↵

On [October 27, 17:05 MSK](http://www.timeanddate.com/worldclock/fixedtime.html?day=27&month=10&year=2017&hour=17&min=5&sec=0&p1=166) Educational Codeforces Round 31 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 [blog post](http://codeforces.com/blog/entry/51208).↵

The round will be **unrated** for all users and will be held on extented ACM ICPC rules. After the end of the contest you will have one day to hack any solution you want. You will have access to copy any solution and test it locally.↵

You will be given **6 problems** and **2 hours** to solve them.↵

The problems were prepared by Ivan [user:BledDest,2017-10-26] Androsov, Vladimir [user:0n25,2017-10-26] Petrov, Alexey [user:Perforator,2017-10-26] Ripinen, Mike [user:MikeMirzayanov,2017-10-26] Mirzayanov and me.↵

Good luck to all participants!



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:biGinNer, 2017-10-28]</td>↵
<td>6</td>↵
<td>175</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:natsugiri, 2017-10-28]</td>↵
<td>6</td>↵
<td>228</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:palayutm, 2017-10-28]</td>↵
<td>6</td>↵
<td>283</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:LHiC, 2017-10-28]</td>↵
<td>6</td>↵
<td>293</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:eddy1021, 2017-10-28]</td>↵
<td>6</td>↵
<td>295</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:Hinata_On_Fire, 2017-10-28]</td>↵
<td><b><font color="green">18</font></b></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:halyavin, 2017-10-28]</td>↵
<td><b><font color="green">22</font></b><b>:<font color="red">-10</font></b></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:dreamoon, 2017-10-28]</td>↵
<td><b><font color="green">33</font></b><b>:<font color="red">-35</font></b></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:kuko-, 2017-10-28]</td>↵
<td><b><font color="green">15</font></b></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:STommydx, 2017-10-28]</td>↵
<td><b><font color="green">12</font></b><b>:<font color="red">-1</font></b></td>↵
</tr>↵
</tbody>↵
</table>↵

259 successful hacks and 368 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:eddy1021, 2017-10-28]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:eddy1021, 2017-10-28]</td>↵
<td>0:02</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:gritukan, 2017-10-28]</td>↵
<td>0:06</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:cyand1317, 2017-10-28]</td>↵
<td>0:18</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:eddy1021, 2017-10-28]</td>↵
<td>0:36</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:zscoder, 2017-10-28]</td>↵
<td>0:35</td>↵
</tr>↵
</tbody>↵
</table>↵

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en3 English pikmike 2017-10-29 18:10:42 70
ru3 Russian pikmike 2017-10-29 18:10:15 74
ru2 Russian pikmike 2017-10-29 17:56:02 2447
en2 English pikmike 2017-10-29 17:55:13 2462
en1 English pikmike 2017-10-26 20:55:31 1083 Initial revision for English translation (published)
ru1 Russian pikmike 2017-10-26 20:51:55 1226 Первая редакция (сохранено в черновиках)