I have created this website (http://cfladders.rf.gd) using Codeforces Api. It has 12 practice ladders . Each ladder contains 100 problems and all problems are sorted difficulty wise. Hope it will help you to increase your problem solving level.
Here a practice ladder means, you have to solve all previous problem to view the next question. So, this site works like previous dynamic a2oj ladders .
1. First enter your codeforces handle in home page, then it will automatically redirect to ladders page.
2. The problem link of any ladder wil direct you to the actual problem link on Codeforces. And after getting it accepted, go to the ladder and refresh the page. Then next problem will be automatically unlocked in the ladder within a second.
Find which ladder is helpful for you and if you have any suggestions please leave a comment.