<> Interview 1 of byte beating back end development practice
When I wrote this blog , I Know , I don't have a second chance .
Original plan 30 Minutes of telephone interview , Finally, he met me 37 minute . The interviewer doesn't follow the routine , I thought I should introduce myself first , The direct result is to ask about the project .
First, I asked about a message board project , How did you do it , What technologies are used . Then ask me what database tables I have （ I've been working on this project for a long time , I have forgotten to have those tables , I said it from the image , Then he found out there was a mistake , I quickly turned on the computer to read the blog I had written before , I told it again , I guess he doesn't think I did this project , After all, I forgot to set up those tables ….）
interviewer ： Your user What is the primary key of a table ?
I ： I used one id Let's do the primary key ,id It's self increasing .
interviewer ： Then he asked me if I didn't use it auto_increment, How can I achieve it id?
I ： So every time you add a new record , go user Look in the table to find the biggest one id value , Then take id+1 For this new record id.
Interview management ： You have to look up the table every time you insert data , Not efficient , You think about it again .
I ： I can't think of it …
interviewer ：ARP What is it? ?ARP How to realize internal management ?
I ： Yes ARP, But how to realize it internally .
interviewer ：DNS What is it? ? How to realize internal management ?
I ： ip Address mapped to domain name , Internal implementation forgotten
interviewer ： Have you learned the principles of compilation ?
I ： I haven't learned yet .
interviewer ： that 's ok , I'll ask you about the operating system . What is the function of memory unit ?
I ： I can't hear it , Quickly say that the operating system has not yet been tested .
interviewer ： that 's ok , Let me ask you the language .java in hashmap How is it achieved ?hashArray and list What's the difference? ?
I ：???? I can only use it , I don't know how ,map It should have something to do with the red black tree .
interviewer ： All right , I'll test your algorithm .
interviewer ： Stack , What is the queue ? What's the difference ?
Algorithm problem 1： Using stack to implement queue .
I ： It can be implemented with two stacks …
Algorithm problem 2： Here's an array 2 3 1 4
5, There are two operations , Add it to the stack , Or pop up the stack , What is the smallest element in the stack ? For example, add it in first 2, The smallest element is 2, Then add it in 3, At this point, the smallest element is still 2, Add it in 1, At this point, the smallest is 1…, If you remove the top of the stack element 1, The smallest element is 2.
I ：dp,dp[i] Before i The minimum value of the item .
interviewer ： Can we not use arrays ?
I ： Let me just build a new stack , Every element added , You can find the current minimum , Add this value to the new stack . In this way, a one-to-one correspondence can be formed .
interviewer ： OK, Here's a string , There may be spaces in it , Replace spaces with abc, Space replication can only be o(1).
I ： I didn't catch him at first , I'll just say you go through it directly , Just replace the blank space .
He said the complexity was too high , all O(n^2) It's over , Let me change it , I really don't understand the meaning of the title , Just say no …
summary ： operating system , Network planning , The database is really the point , There's no point in doing projects blindly , Big companies don't need yard farmers , It's programmers . Make a good foundation , Learning the data structure algorithm well is the positive solution . in addition , Items in your resume , Remember before the interview , Just write a project with the same technology （ I'm at a loss …）.
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