More than 400 pages of ppt made by Li Piji of Nanjing University of Aeronautics and Astronautics. Start with the vector space model, start with the language model, and start with rnn. If you need to make up lessons, it is a good material. For AI-related knowledge content, the quality of free is higher than that of paid ones. It is recommended that you do not waste money.
The original ppt is relatively large, you can reply to " Past and Present " to download and read