Happy gathering time

Hello everyone , I meet you again , I'm the king of the whole stack .

The day before yesterday, several students in the class went to the happy gathering era to take the written exam . I had a try mentality , As a result, I received a notice the next day . After asking the students who went with him, they all said they didn't receive .

Monday I 10：:10 We rushed to Huagong hotel , I am a 10:30 Divide that batch , After signing, wait patiently on the seat . The results are 11:15 I haven't called my name yet . It's only good to ask the front desk if it's called. I didn't hear it （ In fact, the original intention is to urge ）, The staff said they would check , Let me wait outside , The rush really worked , After a few minutes, a staff member called my name .

After going in . The interviewer didn't let me introduce myself , Directly into the theme . He opened Baidu page with his mobile phone . Enter search keyword, With keyword The input of , There is a drop-down list below that shows the prediction search keyword, example ： Enter Guangzhou , The drop-down list will show Guangzhou University ; Guangzhou Haixinsha, etc . Ask what data structure is used to realize this function . At that time, I was stunned , Ask such a profound question when you come , I thought about it and said that I would use the dictionary tree to realize , Then I roughly described the dictionary tree and its advantages .

Here I feel that the description was not very good , The correct approach should be to describe the narrative at the same time . While using paper and pen to describe it concretely , This can deepen the impression of the interviewer , It can also prove that you really understand rather than half a bucket of water with half a knowledge .

The second question the interviewer asked was ： Now there is 15w Your users are connected to your server, ask server How to deal with the sending and receiving of user information .

I'll introduce myself to the interviewer first socket Programming . After the introduction, the interviewer interrupted me and said that you were talking about a user . existing 15w user , How to solve .

I said, ： With multiple threads . Each thread processes a user's request .

interviewer ：15w User connections are loaded into memory . Can you ？ I said, ： If there is not enough memory, you can consider multiple server, Then according to the user's ip The address range is divided into multiple server Top processing . interviewer ： Now suppose there is only one server. One thread , How to deal with . ok , You win . Just a good answer, I don't know how to deal with , And let the interviewer answer how to deal with ： The user's ip Address and port Save up , Put the user on server The initiated request is added to the message queue . Use multiple threads to process messages in the message queue （ According to the saved user ip And port Return to the user ）.

Third question ： Two administrators need to access the salary of employees in the database , If the salary is lower than 3000 Plus 300 Wages . Ask to write sql sentence .

The database didn't learn well , I don't understand . interviewer ： I mainly want to ask how to prevent two people from accessing data at the same time and changing data at the same time .

I just remember to lock the data , As for the locking statement, I forgot .

Then the interviewer asked two more multiple-choice questions in the written exam , Just say it's over , Ask me what else I want to ask him , The whole process is 10 More minutes , I knew it was over .

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