Hello peoples of codeforces, I hope you are doing well. This is my first blog and I want to ask a question: For people who can solve A, B, C Div 2 problems comfortably, how to improve their skills to solve harder problems within the contest time? I usually solve the first 3 problems from 45 minutes to 1 hour, but then I will find myself stuck coming up with a solution to the problem D. Without solving 4 or more problems per contest, I will never reach purple :(. Are there any tips for me to overcome that? Which tags do D problems usually have? What is the average rating of the 4th problems? I would appreciate your helping. Have a nice day.