At present, the fees charged by many training institutions are very chaotic. Teachers in some training institutions will say that tuition fees are very cheap, only about two or three thousand yuan. After you pay the tuition, you will be asked to pay more money one after another. All these add up to much more expensive than ordinary educational institutions. Moreover, you may not learn enough, and the teacher's level is also very average. It not only consumes time, but also wastes money.

Solid basic data structure, discrete mathematics and compilation principle are the foundations of all computer science. If you don't master them, it is difficult to write a high-level program. Everyone can write programs, but when you find it difficult to improve to a certain extent, you should think about whether to go back and learn these most basic theories.