This is the description of the video record and coding challenge.

For the video record, there is only one simplest behavior question.

The coding challenge is a progressive problem, from simple string input processing to finally sorting a string array.

For coding challenges, they first give you one string, using some special characters to separate different stocks, and ask you to standardize them.

Then, the questions become progressively more difficult. For example, you might be asked to select the most profitable stock, with each question building upon the methods learned in previous ones.