I always wanted to make something like a guide for anyone who wants to be better at competitive programming. But I believe that I'm not experienced enough to make this guide.

So, here is what I did and I hope it will be helpful to many of you:

- Out of more than 80,000 rated Codeforces users, I selected just 700 of them who satisfied the following conditions:

- Over the period of 1-2 years, their rating increased step by step more than 600 points in total (their graph looks linear in a period of 1-2 years with increment of more than 600 points).
- They participated in at least 20 rated contests.
- They solved at least 150 problems in practice in this period.

For each rating range, interestingly I found many common problems solved by these users when their rating was in that range. I found the most 100 solved problems in that rating range.

I created a ladder for each range, and the problems inside it are sorted based on an accurate difficulty level I calculated.

I believe if someone manages to solve (or at least understands the solution from someone else or the editorial) all these problems, they will notice some significant improvements in their skills and rating.

You can find the ladders at the top here: https://a2oj.com/ladders

Also please share this with anyone who might be interested.

P.S. I know that a ML model might do a better job, but the reason why I didn't do this, because I didn't have enough data.

**[Edit] I created more ladders, you can read about that and other new feature here.**

Great to see this! I am practicing through a2oj ladders for quite a while now and its working out really good for me as there is a linear rise of difficulty(almost) through this. Infact I finished most of the problems of 1400-1499 ladder and my rating is 1500+ now. Looking forward to next ladder. Thanks a lot for these! :D

I don't really like the fact that i can see all the problems from one ladder...

Is it only me , who can't open the ladder ?

I faced the same problem. You should verify your A2OJ account using email verification and the ladder will be visible again.

How do i verify my account?

Great idea but I'm facing a problem see some of the problems on the 1400-1499 ladder I've already solved but it doesn't show up as a solved problem (for example the "K-tree" problem I've solved it but it's telling me that it's not solved) what should I do ???

Update your solved problems of codeforces at a2oj

How do i verify my account?

Check your email.

Could I kindly request that there are more than 100 problems on the ladder? Or have 2-3 pages of the ladder per each level? I need more practice on some of the sections. Thanks for making such an useful training method!

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