Codeforces Gym
Founded: 2009
Certification Provided? No
About: Go to the "Gym" section and choose a contest to your taste. Pay attention to the stars, they show the complexity of the training session. Order a contest online (as can be done with the usual Codeforces rounds) and proceed to the solution! You will be confronted with other online participants as well as with ghost participants (those who took part in this contest one day and turned up in the Codeforces system due to the analysis of the final standings file of the past contest)..