[Autumn Recruitment Summary] Zhaben Java freshman got his wish and got the offer from Ali and Tencent (dual offer)

Preface

In September and October of this year, I squeezed the updated interview questions in the group every day, and strolled through the interviews at the big factory in the group files. Every day I felt like a song, "Eighteen Bends on the Mountain Road". Click here to join the group for free, secret code: CSDN

I have seen Tencent Tower posted by others and imagined the feeling of Tencent Tower looking out.

I went to the Ali Hangzhou Park during my freshman year, and I was worried about whether I had a chance to go again.

I really didn't expect myself to be confused when I waited for Tencent and Ali again.

One day, a dream come true, think of Ali Park in the sentence, "Thank the efforts they have" .

Interview situation

Tencent (WXG WeChat Pay)

It was the CSIG cloud industry group, which was unexpectedly picked up by the WXG WeChat group. Thanks for the coincidence.

Tencent resume face (programming + 33 minutes 35 seconds)

1. Handwritten OOP in Notepad to implement a sign-in program.
2. From a bunch of numbers, O(n) finds unique numbers.
3. String processing, magic change KMP.
4. For math puzzles, 64 horses take the top 8 and how many times is the fastest to ask. 11 times.
5. Resume, ask what the project did, the main technology stack.

Tencent side (41 minutes and 38 seconds)

• Asked my project in depth.
• Thread pool, connection pool, their advantages.
• Common Java design patterns.
• Talk about the builder mode. This answer is not very good.
• The difference between TCP/UDP and when should I use it.
• UDP implements TCP.
• Design an APP and use TCP/UDP specifically.
• Database index, database engine.
• Learning direction, I said that C++/Java/Python is more balanced.
• What has been done for scientific and technological innovation projects.

I didn't give me a chance to ask questions, maybe I was too good at it.

Tencent two sides (video interview, 75 minutes, mainly writing code)

1. ACM complex rule simulation. You can use the Java Chain of Responsibility model here, but I didn't answer it when I asked it. I have forgotten it.
2. Java GC. Begin to recite balabala.
3. Parent delegation mechanism.
4. Four necessary conditions for deadlock:
5. Mutually exclusive conditions: A resource can only be used by one process at a time.
6. Request and hold conditions: When a process is blocked by requesting resources, it keeps on holding the acquired resources.
7. Non-deprivation conditions: The resources already acquired by the process cannot be deprived forcibly before they are used up.
8. Circular waiting condition: A kind of circular waiting resource relationship is formed between several processes.
9. Exclusive lock, shared lock and update lock.
10. What else do I want to ask. Asked about the technical atmosphere and learning situation.
11. XSS injection attacks do not understand. Answer no.
12. I talked about SSH login for a long time, and the other side said what this method is called. After thinking about it, asymmetric encryption.
13. How many man-hours does it take to implement a face recognition software?
14. To be honest, this aspect of me is almost autistic, some of which have been read and then forgotten.

Tencent three sides (WeChat voice)

1. Process scheduling, process state switching.
2. How to use Java/C++ to implement thread pools and specific methods.
3. Spring framework, ORM framework Hibernate talks about.
4. What is the difference between IOC, AOP, IOC (Inversion of Control) and DI (Dependency Injection), Java reflection mechanism.
5. Adapter pattern (Adapter pattern), Bridge pattern (Bridge pattern), Combination pattern (composite pattern)
6. Mainly ask about the technical direction I want to do.
7. Introduce Tencent's departments and personnel division, etc.
8. HDFS, Paxos*** protocol, zookeeper and redis a little bit.
9. Oral offer

Alibaba

Ali side (38 minutes and 50 seconds)

1. Self introduction + project introduction. Deep learning, SSH framework, C#, Java
2. See you mentioned connection pool, druid connection pool.
3. Common sorting algorithm. Quick queue, two-way merge, bubbling, insertion, and tournament sorting. topK problem.
4. TCP handshake three times and waved four times.
5. Database engine comparison, indexing. Innodb, Myisam and Memory are compared, B+ tree, hash, between operation, left join operation.
6. See you doing ACM, tell me a simple data structure, answer and check the set and the line segment tree.
7. How to ensure the atomicity of multi-threaded operations. Atomic class, lock, volitile partial operation.
8. In-depth questions about optimistic locking, pessimistic locking and their implementation. I mentioned CAS, ABA but don’t ask me hhh.
9. Python machine learning basics.
10. How to solve the dependency problem.
11. Zookeeper lock, database isolation level.
12. Docker isolates the deployment problem.
13. Which factors should be considered for taobao query sorting? This question is difficult for the thief, and there are a lot of things I can say. It is estimated that I read the machine learning on my resume and answered the past consumption records, search records, collaborative filtering, and clustering.
14. What should I add? Consider the situation of the merchant, balabala.
15. What else do I want to ask.

Summary: The questions asked are fragmented but comprehensive, and it is easy to see how well a person has mastery.

Ali two sides (45 minutes and 39 seconds)

1. Self introduction + project introduction. Deep learning, SSH framework, C#, Java
2. What is your advantage over others in the project is that you use things that others do not have.
3. What do you think about your ability? ACM capabilities. I thought I was going to type code. Turn on while talking.
4. How do you learn?
5. Draw the execution process of a software, UML, ER.
6. Have you ever written development documents?
7. How does Java load classes, load verification, prepare to parse, initialize, use unload, and parent delegation mechanism. Bootstrap class loader, extend class loader are specific.
8. Linux commonly used commands. iftop, netstat, htop, apt, yum, source, corn, docker, etc.
9. Talk about docker.
10. MVC, MVVM contrast.
11. Spring的IOC, AOP。
12. Hibernate ORM framework to talk about.
13. Do you understand design patterns?
14. What else do I want to ask.

Summary: This is quite satisfactory. No hard questions are asked. As long as you have tried everything on your resume, you should be able to answer it.

Ali three sides (leader side 18 minutes 59 seconds + 24 minutes 53 seconds)

1. Make an appointment one day in advance
2. Tell me about 40 minutes of interview today, including self-introduction, technical knowledge, and project experience.
3. Self introduction. Scholarships, ACM, deep learning, traditional project development, load balancing optimization, etc.
4. The main content of CSDN and Github you maintain, and the situation of ACM questions.
5. Which of your basic knowledge is better? Every piece is average. . .
6. How does TCP achieve reliable transmission over unreliable network transmission? Retransmit after timeout, sliding window. TCP status.
7. TCP timeout, how to calculate RTT.
8. How does TCP realize traffic changes when 4G switches to Wifi? Packet loss, fast retransmission, fast recovery, etc. The router switch is queued.
9. Common TCP optimization algorithm. The TCP congestion algorithm answers the principles and simple implementation of Google BBR and Rui Speed.
10. The operating system linux kernel optimizes the method of TCP, and each version of HTTP1.0, 1.1, 2.0 is updated. Status 100, host field, 6 TCP connections in Google Chrome, etc., support long connection.
11. The difference between cookie and session in HTTP. The client and the server represent the user's method and what to do when cookies are disabled.
12. On the basis of the previous one, I extended the answer to Redis.
13. The data structure of session storage, for single user set, multiple user hashmap.
14. The principle of hashmap, key-value calculation, and three ways of conflict resolution. Contrast with dichotomous time complexity. Rehash causes the ring.
15. Hashtable thread safety, talk about the implementation of thread safety.
16. In addition to segment locking, there are any other optimizations in the performance of conCurrentHashmap and Hashmap. I only answered the expansion within the segment.
17. Use of hashmap in high concurrency scenarios, CAS, ABA problems.
18. The concept and difference between parallelism and concurrency. Time slice, context switch.
19. Database paradigm, have you ever understood NoSQL?
20. UML diagram, ER diagram, flowchart.
21. The index of the database, the leftmost prefix, and the three primary keys of abc.
22. Common optimization ideas for cross-table query.

Summary: This person speaks in a very organized manner. He is a big shot at the first listen. He is typing interview records throughout the whole process. The overall experience is still very good.

All around Ali (intersection of Tmall supermarket)

1. After introducing myself, let me confirm my profession, education, and phone confirmation. (?)

2. Tell me about your ACM experience.

3. Have you considered the postgraduate entrance examination? You can learn more in the enterprise. I was lost for a while and couldn't hear what the other person was saying.

4. Compare the postgraduate entrance examination and work.

5. How to balance work and leisure time.

6. What did you do in the deep learning project. I have read Hua Shu, Watermelon Book, Introduction to Machine Learning.

7. What aspects can be used in this project, night camera, old photo restoration, etc.

8. Do you know the Java development framework? SSH, SSM. Expanded dubbo, durid, rocketMQ, Netty. I have answered too many questions on this question, and I have been working on it for a long time.

9. volitile guarantees the visibility of memory, prohibits instruction rearrangement, ***.

10. Memory barrier. I don't know directly, I really don't understand the great god. . .

11. Talk about rocketMQ, priority queue, Filter, Persistence, Reliablity.

12. How to do message consistency. Ensure idempotence.

13. Retrospective consumption. Retrospective consumption refers to the news that the Consumer has successfully consumed, and it needs to be consumed again due to business needs.

14. The difference between wait() and sleep(). yield method.

15. Comparison of lock and synchronized.

16. Re-entry lock, bias lock, coarse lock.

Summary: The problems are very good, comprehensive and in-depth. However, I am too good at it and I got a few wrong answers.

Ali HR noodles

1. Introduce yourself to ease the embarrassment.
2. ACM, the content of learning, the situation of the paper.
3. Learning methods, practical methods.
4. What is the difference between the middle and high school algorithm competition and the university competition.
5. How do you teach yourself the law.
6. How to balance work and study.
7. Huashu, what is the main content of the introduction to machine learning? The talk is relatively shallow, but HR asked a point. (HR also understands technology, heavy fog)
8. Contributions to the computer club you led during the university.
9. In terms of social practice, "Top Ten Teams", the content and process of the entire activity are explained.
10. Other general issues.
11. What I want to ask is the situation of department personnel.
    

to sum up

For a few days in March, what should I do if I worry about being picked up every day and cannot answer the interview call? What should I do if I hang up without talking? Why are you still in the resume pool?

Why are others not as good as I can go ashore. In fact, it was because I was not strong enough, so I thought about it and went to study. A lot of learning materials are also organized here. If you need it, you can click here to get it for free. Code: CSDN

Those who need the above information can click here to get it for free, code: CSDN