This training ladder is made after the order of solved problems by a user who has solved all the problems up to 2399 rating on AtCoder (in about ~3 years) and is now a blue coder. Beginners often want an approachable ordering of problems to solve. Follow this ladder to practice blindly. If you solve this entire ladder, congratulations, you'll also end up solving almost all problems up to 2399 rating. The solve date and time reflects the actual timing of the user who solved these (Problems before ABC042 and ARC058 are excluded).