I often see blogs and comments in Codeforces community mentioning and referring to problems from Grand Prix of many places. Even there are frequent blogs discussing solutions of many Grand Prix contests. Reading these discussions, it has seemed to me that the problemset of these contests are quite interesting and full of new ideas. But unfortunately I could find no such contest in neither Codeforces nor Gym.
Which site actually hosts this contest and what is the procedure of participating in it ?
Is there a way to submit in these contests later ? Thanks in advance.