Hi Codeforces!

I am really pleased to introduce My research project called PROPER

• This is an web application that recommend you some problems that have adequate difficulty to practice. After you solve the recommended problems you may give PROPER your feedback that the problem is Hard/Adequate/Easy. This feedback will be used to make better recommender system.

• System automatically collect status data from CodeforcesAPI, and calculate adequate problems to user personally, Problem is recommended based on your status and other coder's status interactively.

• We use Matrix Factorization algorithm which is one of the famous recommender system model.

the PROPER address is: http://recommender.cf

I've evaluated this system in statistical way and it was quite good.

So I'd like to survey about this system for actual users.

I hope it works well for users and this system helps you practice better.

Thank you for reading!!