Hello Codeforces!

On February 16, 18:05 MSK Educational Codeforces Round 38 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

This round will be rated for Div. 2. It will be held on extented ACM ICPC rules. 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 7 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov, Sahand Xahandd Alitanloo and me.

Thanks Mike MikeMirzayanov Mirzayanov for great system Polygon!

Good luck to all participants!

UPD: Since there will be another Div. 2 contest soon, the hacking phase will be shorter (only 12 hours). Before CF Round 464 we will actualize the registrations in such a way that Div. 2 will be officially registered, and Div. 1 participants — unofficially.

UPD2: We also have a message from our partners Harbour.Space:

We are excited to announce that some of the world’s strongest teams will come to our Hello India x Russia Programming Bootcamp: MIPT and all top India’s Universities that qualified to the World Finals!

As always, the boot camp isn’t only about the training — we’re in the process of getting renowned keynote speakers from all over the globe to come and speak about life and all the opportunities at your fingertips after ACM-ICPC.

We look forward to seeing you all there this spring! For those of you who haven't registered, there's still time.

Register here

If you have any questions we can help you with, please connect with us:

Phone number: +34 674 291 422 Email Address: hello@harbour.space

UPD3: Editorial is published

Hello Codeforces!

On December 28, 17:05 MSK Educational Codeforces Round 35 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

This round will be rated for Div. 2. It 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 7 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov, Vladimir vovuh Petrov, Alexey Perforator Ripinen and me.

Thanks Mike MikeMirzayanov Mirzayanov for great system Polygon!

Good luck to all participants!

We also have a message from our partners, Harbour.Space University:

Hello everyone!

Registration is open for our upcoming 1st Hello India x Russia Programming Bootcamp, with 20 teams signed up and counting, and we are looking forward to seeing you and your teammates in India this March!

More information

Register here

UPD: There will be 7 problems!

Congratulations to the winners:

Congratulations to the best hackers:

1761 successful hacks and 1237 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

UPD2: Editorial is out

Hello Codeforces!

On October 27, 17:05 MSK Educational Codeforces Round 31 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

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 BledDest Androsov, Vladimir vovuh Petrov, Alexey Perforator Ripinen, Mike MikeMirzayanov Mirzayanov and me.

Good luck to all participants!

Congratulations to the winners:

Congratulations to the best hackers:

259 successful hacks and 368 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

UPD: Editorial is uploaded

Hello Codeforces!

On October 12, 17:05 MSK Educational Codeforces Round 30 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

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 BledDest Androsov, Vladimir vovuh Petrov, Mike MikeMirzayanov Mirzayanov and me.

Good luck to all participants!

Congratulations to the winners:

Congratulations to the best hackers:

123 successful hacks and 96 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

UPD: Editorial is published

Hello Codeforces!

On August 21, 18:05 MSK Educational Codeforces Round 27 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

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 7 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov, Vladimir vovuh Petrov, Mike MikeMirzayanov Mirzayanov and me.

Good luck to all participants!

Harbour.Space also has a word for you:

We are delighted to welcome the 2017 ACM-ICPC World Champions, ITMO, to our 2nd Hello Barcelona Programming Bootcamp in collaboration with Moscow Workshops ACM ICPC starting September 27.

All the top Russian teams are coming, including St. Petersburg State University, MIPT, Ural Federal University, Tomsk, Novosibirsk, Saratov and Perm, as well as the world’s top universities such as Waterloo, Central Florida, Hangzhou Dianzi, Singapore, KTH and dozens of others — so far teams from 30 countries have signed up.

The event’s gold sponsor is Sberbank, the biggest commercial and investment bank of Eastern Europe and Russia. Thanks to their support we expect that the top participants will be awarded valuable prizes, alongside high-profile internship and job opportunities.

We can’t wait to see all of you coming to learn, practice and compete on the international stage, smoothing your road towards April World Finals in Beijing.

Ps. Registrations close on September 1.

UPD: Editorial is published

Congratulations to the winners:

Congratulations to the best hackers:

1326 successful hacks and 300 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

Hello Codeforces!

On August 3, 18:05 MSK Educational Codeforces Round 26 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

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 7 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov, Alexey Perforator Ripinen, Mike MikeMirzayanov Mirzayanov and me.

Good luck to all participants!

Don’t miss your chance to be a part of this leader board in the next ACM-ICPC World Finals by reserving your spot in the 2nd Hello Barcelona Programming Bootcamp in collaboration with Moscow Workshops ACM ICPC.

Check out the winning statics of Universities that participated in this special training — World Finals 2017 Results.

8 out of 12 prize-winners of the World Finals 2017 participated in Moscow Workshops ACM-ICPC!

Take a look back on our previous "Hello Barcelona ACM-ICPC Bootcamp, in collaboration with Moscow Workshops ACM-ICPC". Students and coaches from all over the globe gathered at our campus to learn from and work with the world’s top programmers, soak in the Barcelona sun, and share in the comradery built within the programming community. Harbour.Space University is looking forward to hosting again, this time at the beautiful and technologically mind bending Media-TIC building.

UPD: Editorial is available

Congratulations to the winners:

Congratulations to the best hackers:

1361 successful hacks and 513 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

Hello Codeforces!

On July 16, 18:05 MSK Educational Codeforces Round 25 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

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 7 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov and me.

Good luck to all participants!

UPD: The editorial can be found here.

Congratulations to the winners:

Congratulations to the best hackers:

929 successful hacks and 587 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

Hello Codeforces!

On April 28, 18:05 MSK will be held Educational Codeforces Round 20.

Series of Educational Rounds continue being held as Harbour.Space university initiative! You can read the details about the cooperation between Harbour.Space and Codeforces in the blog post.

Here is the special message from Harbour.Space University for girls from India:

Harbour.Space University offers a unique opportunity to win a FULL SCHOLARSHIP for #womenintechIndia and join our amazing Data Science, Computer Science or Cyber Security Master's Programme in Barcelona, Spain!
Follow this link to complete the application form.

The round will be unrated for all users and it will be held with extented ACM ICPC rules. After that 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 7 problems and 2 hours 15 minutes to solve them. Though this round may come a bit harder than two previous ones, we still hope that everyone will enjoy problems.

The round was prepared by Ivan BledDest Androsov, Mikhail MikeMirzayanov Mirzayanov and me.

Good luck!

UPD: Editorial is available here

Congratulations to the winners:

Congratulations to the best hackers:

324 successful hacks and 209 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

Hello Codeforces!

On April 15, 17:35 MSK will be held Educational Codeforces Round 19.

This Educational Round is held as Harbour.Space university initiative. It's the second round supported by Harbour.Space. You can read the details about the cooperation between Harbour.Space and Codeforces in the blog post.

Some educational programs in Harbour.Space are interesting for most Codeforces users. One of them is Data Science Program. Here is few words from Sergey Nikolenko, Harbour.Space lecturer and Senior Researcher, Steklov Institute of Mathematics at St. Petersburg Russia.

The round will be unrated for all users and it will be held with extented ACM ICPC rules. After that 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. We tried to prepare such problems that both novices and experienced coders will find something interesting in this contest.

The round was prepared by Ivan BledDest Androsov, Mikhail MikeMirzayanov Mirzayanov and me.

Wish you enjoy the contest! Good luck!

UPD: Editorial

Congratulations to the winners:

Congratulations to the best hackers:

234 successful hacks and 308 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

They do! In some way.

For eager ones link to userscipt.

Hi everybody!
You know, our universe is pretty unfair place. Luckily, some unfairness can be fixed. And I found a method to make this world a bit kinder!

Let me introduce a plugin that can help people overcome difficulties in their lives and develop their self-esteem!
I believe, every active member of codeforces community at least once faced the problem I've faced couple times. It's when you try to reach that sweet green arrow to support commentator but instead of this you accidentally punch the red one with all of your might! And there is no way to correct the mistake!

So, I spent some time studying the problem (and jquery, btw) and made a cute little script that changes concept of vote confirmation. While you are on a page, you now can alterate between your decisions as much as you wish (though only on comments you haven't voted for before entering page). Changes will be applied on site closing (it can be either moving to other site or closing tab/browser).

I'm not sure about the reasons but the fact is that sometimes not every vote is being applied. To prevent loss of your grades I also added special button to save everything. It can be found on panel with new comments counter (or in that place if there are no new comments).

I will dublicate link to script, if you miss it in the beginning. It's a simple userscript that can be run in chrome-based browsers (via tampermonkey plugin), firefox (greasemonkey) and opera of older versions (violentmonkey).

If you found any bugs or have some suggestions feel free to notify me via pm or in comments.

Happy New Year!

Introduction

Hi everybody! Recently I have decided to refresh memories about good old times and play Gravity Defied on my phone. It wasn't really hard to find port of that legendary game from J2ME to modern platforms. It rapidly gained glory among students of past decade. Key points of Gravity Defied success were nice gameplay (biker completing different stages with high cliffs and deep pits), convinient physics (ability to rotate mid-air) and simplicity of modmaking. As for me, it was a bit more than usual game. When I had completed over thousand tracks, I began earning money on helping others to progress. Only later even more difficult games were developed: HOMM 3, Far Cry and Dark Souls...

Predevel story

And now Gravity Defied is on my phone again! Not original, though, but well-made remake for Android. I can totally declare that atmosphere of game was transferred great! And one more time I got sucked into game so badly that I imagined biker each time I had seen polygonal path. One day, when I was waiting for rating recalculation after Codeforces contest and looking at graph on my profile page, I got an idea to use that graph as track. Just wanted to live through all the victories and defeats of past two years of competitive programming again...

Development

When I finally start to think about general concept of program, I realized that I know nothing about neither modding itself nor Gravity Defied track creating. So, Internet has everything, I thought... Firstly, I discovered that track files differ in two Android versions of GD (official from CodeBrew and unofficial from VKontakte developers, which is better in my opinion). And while .gdlvl for official was pretty easy (it's using most appropriate JSON extension), .mrg for unofficial (and for that J2ME game also) was truly comlicated! The thing is that there are very few useful forums (I found only one topic on russian forum and one wiki page which helped me at least in something). I got needed piece of information translated and proceeded with implementation. Python 3 script loads JSON with contests list of certain users and creates array of points using information about rating change and period of time between contests. All libraries used are built-in (os, sys, time, urllib, json). Being executed from console, it can either read handles from file or from command line. Installation guide along with script itself can be found here.

Some screenshots:

Please, notify me about found bugs in script and errors in post by PM.

Good luck and have fun!