A web app developed using Flask that compiles all the Problems on Codeforces that you have attempted (submitted at least once) but could not get Accepted verdict. For convenience, the problems can be segregated by Index (i.e. A, B, and so on) OR Rating (i.e. Less than 1000, Between 1000 and 1200, and so on). Unattempted Recommended Problems are displayed in Recommended Section. Click on the Problem Name to visit the original problem page on Codeforces, solve it, come back here and repeat. Good Luck and High Rating!