Sorry, I haven't heard of this. It depends on whether you choose training or general books and textbooks.

Generally, the textbooks on the market feel similar, mainly to see which ones sell better, and then to see which ones you think fit your own thinking according to your own problem-solving habits, and then make a choice.

If it's training, you need to be lucky enough to run and compare more. The big one is not necessarily good, and the small one is not necessarily bad.