Everyone wants to enter a big factory, and of course I am no exception. As early as the spring recruitment, I had put a lot of resumes to such and such big factories, but unfortunately, during the epidemic, they were interviewed remotely, and I had problems at that time, which led to repeated investments and failures. Suddenly I realized that there was nothing in my stomach, and I asked if everything was Kaka Kaka. Later, I made up my mind to make up for my knowledge and IQ. I got stuck in the pile of books every day, plus practical exercises, I felt pretty good. ,better.
Especially this [Java Advanced Core Knowledge Collection] (shared at the end of the article) , which I have been gnawing on for a full 58 days , was shared with me after a friend interviewed and entered a major factory. After familiarizing with nearly 30 categories of Java knowledge in it, in late July I mustered up the courage to attack the back end of Douyin, and the 123 faces (video faces) seemed to be broken (lucky). After finishing the work, I sorted out the Tik Tok 3 faces, I think you can refer to it.
The back side of Douyin (7.22) (47 minutes)
1. The screen went black before I finished introducing myself. . Ask questions directly after reconnecting. .
2. The underlying implementation of hashmap
3. Java thread pool parameters and specific usage process
4. Why not use b tree, b* tree, but b+ tree at the bottom of mysql.
5. Wrote a sql statement (very simple query of join table)
6. In sql statement, table comma table, how will sql be optimized
7. How does mysql bottom layer do when connecting
8. My memory is not very good, I forgot a lot of questions...
9. Algorithmic questions:
(1) Classic [1,2,2,2,3] find out more than half of the elements in the array
(2) Given a positive integer n, ask how many binary search trees consist of 1-n
Douyin Two Sides (7.23) (60 minutes)
1. TCP three-way handshake
2. Why didn’t it work twice? (This is a classic question, but the language has not been organized and the language is nervous, resulting in a little messy answer)
3. Understanding of java synchronized keywords
4. Introduce AQS
5. The specific process of AQS blocking when the lock cannot be obtained
6. The basic data structure of redis
7. Hot data
8. How to realize the bottom layer of zset
9. Time complexity of zset fetching a single data
10. The principle of skip table
11. Message Queue
12. mysql index leftmost prefix match
13. Some questions have forgotten...
14. Algorithmic questions:
(1) Left view of binary tree
(2) For coins with face value [1,3,4], input n, and output the minimum number of coins that make up n and the coins made up
Three sides of the back end of Douyin (7.27) (85 minutes)
The three-sided interviewer looked more serious, first looked at the resume and started to ask about the project.
Asked about the leftmost prefix of the mysql index (I vowed to say my understanding, and later found out that I seemed to have deviated, vomiting blood)
1. The merging of two binary trees (I will directly talk about layer sequence traversal)
2. Design questions, design a class (there was no point to get the interviewer at first, but fortunately the interviewer gave a hint)
3. Puzzles, 100 coins, 30 positives, 70 negatives. Question: Divide into two piles (distribute at will), turn over one pile, and have the same number of coins facing up. Ask how to divide.
The overall feeling is that one or two sides are more comfortable, and three sides are stuck (personally not ideal), so I personally feel that the foundation is very important, and it must be polished, and then the advanced part of the theory and practice can be combined with half the effort. Two days after the interview, HR notified me that it had passed. . It boils all at once. . Hahaha. . So when it comes to this, there may be a lot of friends who are curious about what I said at the beginning of the article **[Java Advanced Core Knowledge Collection]** which is sacred for 58 days, well, let me show you (notes) If you think it’s good, I can share it with you for free. If you need it, click here to get it for free. The code: CSDN will reply you immediately.
Java advanced core knowledge set
Too much content, there are nearly 30 topics of Java core knowledge collection, not to mention, come to a super long catalog, seeing is believing.
About the algorithm
Byte must-have algorithm, so for the algorithm, we still have to go to the dead, the best is to use the "Algorithm Brush Questions LeetCode Chinese Version" and Zuo Cheng Yun Dashen's "Programmer Code Interview Guide IT Famous Enterprise" Algorithm and data structure problem optimal solution (nearly 200)"
First look at the "Algorithm Brush Questions LeetCode Chinese Version" in my hand
The content includes: linear table, string, stack and queue, tree, sort, search, brute force enumeration, breadth first search, depth first search, divide and conquer, greedy method, dynamic programming, graph
Algorithm Brush Questions LeetCode Chinese Version
"Programmer Code Interview Guide IT Famous Companies Algorithm and Data Structure Problem Optimal Solution (nearly 200)" by Zuo Chengyun Dashen
The topic is as follows
PS: You can challenge yourself, without looking at the answer analysis (with source code), try if you can handle it
Want to get a complete source code answer analysis + LeetCode Chinese version + [Java Advanced Core Knowledge Collection], etc., like + follow, click here to get it for free, password: CSDN can get it for free