In Codeforces Round #604 (Div. 2) I was able to solve A,B and C problems and I received 1314 rating.

I have given total 3 contest on codeforces.

- contest 1 — solved only A,
**rating — 1370**,**rank — 5680** - contest 2 — unable to solve any problem,
**rating — 1255**,**rank — 4168** - contest 3 — solved A,B and C,
**rating — 1314**,**rank — 2165**

*Despite solving more problems and getting better rank in contest 3 than in contest 1, why my ratings are less than that of contest 1 ?* __

Rating is an accumulative metric of how well you're doing. You start at 1500 when you create your account. Your first contest resulted in -130 drop. Your third contest resulted in a +59 increase. Your rating change can be a metric of how well you did in a competition, not your rating's absolute value.

But it didn't started from 1500 in my case in my first contest i got +360 but it showed 100+360 as my result not 1500+360. Can u please explain.

its because of new rating system . your new account rating will be 1400 . but you will get that after finishing first 6 contest . ( in every contest in first 6 you will get some rating from 1400 )

here is the detailed post about new rating system : link

I got that from 0 not 1400

in your first 6 contest you will get some point ( which total sum id 1400 ) 500,350,250,150,100,50 (in total exactly 1400)

you have to attend at least 6 contest to get that … ( you may loss or gain some more rating depends on your performance )

I have attended more than six contests, but haven't got 1400 rating

Because your performance was really bad in the last 6 contests. So you lost a lot of your original 1400 rating.

Will educational round also be one of 6 contests? I have attended 6 contests,(one is educational,one global contest), but I haven't got 1400 rating

Yes you have attend 6 contests and also got 1400 rating point. But your performance in those 6 contests is not well enough to become a 1400 rated contestan. Just think that way, initially you got 1400 point but you lost some point in every contest because of your bad performance. Now your point is your real rated point.

You find that you got some positive point your past contests but actually you got negative point. Its for new rating system. Details about new rating system in my main comment. Read the blog in that link.

if i solve a,b,c in div.2 can i increase my rating to 1800??

No. You need to solve A,B,C and D to maintain yourself at 1800-1900. If you solve A, B and C fast you could probably reach 1600-1700.

same in my case I have given only one contest and my contest rating is +371

Is the net change of the ratings after the contest is 0?

I think you need to solve 4-5 problems per raund. It depends on the number of problems and how many participants solved it.

I think solving 4-5 questions in a round would make you candidate master

Oh, then I hope to achieve this rank when I come back to rounds!

4 problems in 1-1.5 hour. 5 problems in 2 hours to become purple

Solving A,B and C below an hour should increase your rating, or at least wont lower it, however doing A,B,C and easy D is when you really climb. Also your rank is lower, because rank is acummulative, and before ranking you always start at 1500 rating

I can regularly solve 2 questions in a div 2, A usually within 15mins say. My rating is still bad

(Please dont stop downvoting this)

Forget that. I now know how to view my own contedt history. I feel like have solved 2+ questions every contest

You solved 0 in the last to last contest and your rating dropped by 79. I hope you don't just leave a contest after getting your first question wrong; sh*t happens to everyone.

Well if you look at that contest, it was because his solution to A failed system tests. Be careful making that assumption about him.

I was just making a general statement. It happens to the best of us.

How much problems you should solve to get 1700+ rating isn't a very good comparison.Rating change is determined by who got better than you and who got lower than you. Solving 4 problems in an easy Div 2 may decrease your rating, but solving only 3 in a hard Div 2 can increase your rating a lot. Something that may be a better comparison is your rank, because the distribution of ratings of Div 2 are very similar from contest to contest.

Is there any time constraint involved in calculating the rating change after each contest or is it only the rank that determines it?

The rating is determined by the rank. The rank is determined by the total number of points, which takes into account how much time you spent solving the problems.

Hi, Iam practising from a long time but Iam not able to solve problems. Anybody please suggest something.

nah you only solved only 6 problem harder than 800+

definitely not enough

Iam unable to solve, what to do??? Practice!????

Go for 900-1200 and gradually increase from there

Not necessarily solve every problem you read. Try every approach you can think off before giving up and move on to another problem.

Editorial is optional

I have done 200+ questions of 1800-1900 rating, but still i am stuck at ~1750. In some contests, i perform bad and lose rating and in another i gain rating, my graph is total zigzag. Please anyone guide me how to improve further.(This is my practice account, so don't consider my rating as 1580. It's 1750 on my main account.)

Only 1 problem is needed if you can solve the last problem (usually F or E).

EDIT: don't focus too much on A and B, they are just waste of time

Please don't downvote such blogs