Hello, I am a non-Chinese user. I want to know how to choose topics to practice in Lugou? Is there a roadmap or ladder similar to codeforces? I like Lugou because people share solutions and explanations there. I'm (newbie) in codeforces. And want to be able to solve problem till NOI-.

您好，我是非中国用户。我想知道在卢沟怎么选题练习？有没有类似于codeforces的路线图或阶梯？我喜欢卢沟，因为人们在那里分享解决方案和解释。我是 codeforces 的（新手）。并希望能够解决问题直到 NOI-。