Hello everyone! Codeforces Round #FF(255) is coming soon! We invite you to participate in this round, the round will be held in both divisions.

In this round, the boy DZY appears again! As we all know, he loves many things. This time he also brings us many interesting problems, which are easier than the problems in last round, but he still needs you help. In return, he will present rating to you.

Many thanks to Gerald for giving us much advice and helping us to prepare the round. Also many thanks to MikeMirzayanov, who created such a wonderful platform.

The problem setters are jcvb, jiry_2 and me. This is our first Codeforces round :)

Come and join us in helping DZY again, and you will take the high rating home!

Good luck and have fun! :)

UPD

In Div. 1, scores for each problem will be 500-1500-1500-2000-2500.

In Div. 2, scores for each problem will be 500-1000-1500-2500-2500.

UPD

The contest is over. Thanks for participating.

Congrats the winners.

Division 1:

1. vepifanov
2. subscriber
3. RAVEman
4. ztxz16
5. anta

Division 2:

1. llllllllllll
2. geniucos
3. Misha100896
4. Temirulan
5. wwt15

You can find editorial here.

Hello everyone! Codeforces Round #254 is coming soon.

In this round, there will be a really cute boy named DZY. He loves many things, we can even say everything. He has a great passion for the gorgeous world, but he can't deal with everything he's interested in. So he needs your help, and he will present rating in return.

My thanks go to Gerald, who gave me much advice and helped about the problems. And I also would like to thank MikeMirzayanov, who created such a wonderful platform.

The problem setters are FancyCoder and me, and thank vfleaking, jqdai0815 and lsmll for testing.

Come and join us in helping DZY.

Good luck and have fun.

UPD

In Div. 1, scores for each problem will be 500-1000-2000-2000-2500.

In Div. 2, scores for each problem will be 500-1000-1500-2000-3000.

UPD

For technical reasons, the round will be delayed by 5 minutes.

UPD

The contest is over. Thanks for participating.

Congrats the winners.

Division 1:

1. subscriber

2. flydutchman

3. uwi

4. Egor

5. stevenkplus

Division 2:

1. lost3030

2. laekov_

3. JongMan

4. Daumilas

5. nnahas

You can find editorial here

Oh yes! Only a few days left before the Championship finals! The teams have already gathered in Yekaterinburg, most of them have registered and are watching a game between Russia and Belgium.

I want to start from some history and remember that the tradition to publish travel notes about Saratov State University's trips to finals started back in 2005. The regular pattern is that almost every year when we made notes, our team won a medal. I won't try my luck, so here are some of the first impressions of this year.

Hello!

We invite you to participate in Codeforces Round #253, which will take place on Thursday, June 19th at 19:30 MSK. The round will be held in both divisions.

It's my first Codeforces Round and I hope you will enjoy it!

Many thanks to Gerald for helping to prepare the round. Also I'd like to thank MikeMirzayanov for creating such a good platform. Also thanks to testers of this round: antonkov, Aksenov239, VArtem, subscriber, niyaznigmatul and to Delinur for translating statements.

Don't miss a chance to have fun of solving interesting problems!

UPD. Score distribution:

Div1: 500-1500-1500-2000-2500

Div2: 500-1000-1500-2500-2500

UPD2. The contest is over, thanks for participating!

Congtatulations to Div1 winners:

1) tourist

2) scott_wu

3) stevenkplus

3) gs12117

5) GlebsHP

And congratulations to Div2 winners:

1) tafit3

2) thnkndblv

3) MIT3

4) lucaslima

5) liuzhijian

My congratulations to tourist, only person who managed to solve all five problems, and only one who solved problem 442E - Gena and Second Distance!

You can find editorial here.

Today, on June 15 at 1 p.m. MSK the last round of Yandex.Algorithm elimination stage will begin. Crucial for determination of Yandex.Algorithm finalists 718 score points will be distributed during these 100 minutes. Three prize-winners of Yandex.Algorithm 2013 have already reserved a place in the final round. Have you?

Preparing a contest is not as popular a topic as the perennial question of "how to become red in three months", but still it stirs some interest in Codeforces community now and then. Earlier I've written about preparing Surprise Language Round and about emotional aspect of problemsetting; now it's time to share some facts about running regular contests.

Problems

How much time does it take to prepare, select, recall or find problem ideas?

How much experience solving competitive programming problems is necessary to be confident about inventing problems of your own?

Idea generation is a long-term, nearly continuous process. A couple of years ago when I was still an active problemsetter I used to create ideas from literally everything (a squirrel running... hey, this could be a great problem! — seriously, the problem is still there in my drafts, and a pretty complicated one) and to write them down. Then when I had time and inspiration to run a contest, I went through the drafts looking for ideas which would be 1) solvable and 2) nice and unusual enough, and combined them in a problem set.