How DO I hire Programmers?

In the previous part, we talked about some ways to get to know people (operation, knowledge, experience, ability), and some ways to interview people (algorithm questions, challenges in actual production activities). Now let’s talk about the style of interview, and some comments.

Treat the candidate like a colleague

In some companies, interviewers will ask you an algorithm question during the interview, then wait for you to solve it, and if you give an answer, then they will ask you if you have a better answer, and if you give the right answer, then they will ask you a harder question, and so on. They rarely give you any hints and even challenge you constantly, making the candidate nervous.

In addition, there is no right answer to many questions, or there are more than one way to describe the same answer. Many interviewers will feel that you don’t give them the answer they want, so they will dismiss you, act like you can’t do it, and have problems with your skills. This is ridiculous. For example, when answering the question of what is asynchronous, a friend of mine gave an example that an asynchronous call cannot be processed and returned, and a callback function needs to be passed to the caller so that the callback notifies the result after completion. There was nothing wrong with this answer, but it was not the answer the interviewer wanted. The interviewer was not satisfied with it, and then thought that my friend needed to read more books.

I’m sure most interviewers would do the same. I’d like to ask this interviewer, have you ever interviewed your colleagues? In your work situation, do you use interview style to communicate and speak to your colleagues? Let’s ask ourselves the following questions:

• When you met a problem at work, how did you solve it? Do you discuss it with people? Can you get the optimal solution in 15 minutes?
• Have you ever been confronted and pressured to solve a difficult problem at work?
• Do you give your colleagues a hard time at work? Does it make your colleagues nervous? Do you think you can work well under stress?
• Do you feel at work that your colleague’s answer is not the answer you want, is not the answer that fits you, do you think your colleague is not good?
• What was your upbringing like? Growing up under pressure and being questioned every day?
• We all know the disadvantages of exam-oriented education in schools. Do you think your interview is a kind of exam-oriented education? (See how many candidates are doing all kinds of algorithms. Isn’t that a test taking?)

Think about your day job, ask yourself these questions, think about your own growth, think about how you relate to your colleagues, think about what your day job is like, and trust that you can draw your own conclusions.

If you think of the candidate as a future colleague, here are some things you can learn from your interview:

• The atmosphere of the interview will be good, and the candidate will be relaxed, natural and more accepting of the real situation.
• The exchanges and interactions (as opposed to questions and answers) in an interview will give you a fuller picture of a person.
• Non-test interviews will tell you more.
• Get to know a person truly before you can come to truly correct conclusions.

Learn from the candidate

Here are a few ideas

• The interview process is a process of learning from each other, not one where you embarrass the candidate.
• Question and answer is a very rigid process, mutual discussion and learning, good interaction is a good interview process.
• The interviewer isn’t trying to prove how strong or smart you are, it’s trying to tap into the candidate’s strengths and abilities.
• Interviewers should come up with a standard answer to their own questions and see what the candidate can bring to the table.
• Always learn from the candidates, not from them.

No matter how great you are, you’re so easy to pin. Difficult questions are not the end, and they are easy to stumple. Difficult questions are just a means to get a sense of a candidate’s abilities, not the whole interview.

I wonder if you like some competitive sports? Such as playing football, basketball, badminton, chess and so on, what kind of people do you want to play with? Is it bad or is it strong? So, being able to learn from the interviewer and enjoy working with the interviewer is the real purpose of the interview.

For a team, if everyone has the same ideas, opinions and tendencies, the team will eventually become a closed one. If you can’t really accept people with different ideas and opinions, you will lose the opportunity to make progress. How can your team have out-of-box thinking if you’re always hiring people who are just like you? The world is better because it is different.

On the other hand, as a company, if the people you bring in are not as good as the people you already have, how can you as a company have better people to move your company forward?

Therefore, the interview should be a process of learning from the interviewer. Of course, if you can’t learn anything from him, then teach him something. This way, even if the interview does not pass, the interviewer will be happy to accept. Otherwise, let the interviewer get in a bad mood and go out and say bad things, which will hurt your image and the company’s.

Some comments on that

The following is my reply based on the article of some interview questions of Cool shell, as well as my friend’s experience, and some comments on this article about douban’s product manager. You can see how well I can see things from these places.

Cool shell’s answer to the interview question

First, cool shell’s “matchstick interview question”, which is actually very boring. Focus on your understanding of code logic. This post received thousands of replies because the answer is visible. From the reply, I read:

• Some friends can’t think of the answer directly. I can see that there are some friends who are used to acquiring knowledge and not used to thinking independently. Even fear of difficulties, on the other hand, we can see that our education is really not generally poor.
• Some friends think not. From this point of view, I think it is normal, especially to come up with two kinds of, I can feel that they think hard, maybe also made some attempts. It’s pretty good. Unfortunately, I can’t see the way you think, whether you draw a picture on a piece of paper, compile a program and run, or what. I’ll get to know you better.
• Some of my friends gave wrong answers. This suggests that this friend may not like to take tests, may take things for granted, or may be impulsive and not rigorous enough. How much effort can verification take for such a simple program?
• There are a few friends did not understand the question requirements. This shows that these friends are careless and may misunderstand needs and what others are saying at work. Communication problems.

Say again that “train carries coal” question, this interview question I think is mainly to see everybody’s solution idea, expression ability.

• First of all, I was very surprised that someone did it very quickly with mathematics, which is very good, this person has a very good background in mathematics. People who can solve problems mathematically are generally people with strong algorithms.
• Some people complain that I didn’t say the train could turn around, so I didn’t think of such a method. I would have given you a hint if it was in an interview. I’m not gonna dismiss you for not knowing the unspoken rule of turning around. Of course, if you can think of it means that your brain is relatively clever.
• There are also many people who say that his method is rather primitive, that he only transported 400 tons of coal, 416 tons or 333 tons, but he didn’t look at the hint at a glance. I think these people can find a way through independent thinking, and they are actually quite good. It’s only a matter of time before we optimize along these lines.
• More encouragingly, I have seen some friends compare their own methods to others’ better ones and find out why their own methods are not as good as theirs. I think such people know how to “summarize” and “compare”, and such people are always learning and improving themselves.
• Someone else talked about dynamic programming, if it is in the interview, I would like to learn from this friend to use dynamic programming to solve this problem.
• Some friends said that the train can only turn around where there is a station. At first glance, this friend is either a person engaged in needs analysis, or a serious person. Need to know more. However, this kind of friend’s observation ability is very good.
• And some of my friends got it right. But the expression aspect is more complex, some did not understand. It can be seen that the ability to solve problems is some, but the ability to express needs to be improved.

Interview for product manager of Douban

In the article on Douban, the interviewer asked a big question, and the interviewer was not satisfied with the answer given by the applicant, and imposed something on the applicant with his subjective consciousness, and constantly pester the applicant. Later, the interviewer replied, “We focused on two questions: one is the criteria and methods of judging things; The second is the product manager’s pressure response under a variety of PK “.

Here’s what I observed:

• First, this kind of specious benevolence, wise people see benevolence, ten thousand people have ten thousand answers. So, it’s hard to have a standard for answering any question, and I think douban’s interviewers are using questionable criteria to test candidates. A better question: Compare sina and Twitter.
• Second, multiple ideas PK stress response. There is no problem with this. If I have the opportunity, I would like to ask the interviewer whether the product managers of Douban are entangled in this way. If that’s the case, then I’m worried about you.
• Thirdly, it is obvious that the candidate does not know what the interviewer is trying to say, so the candidate always gives some ambiguous answers. Very politician answer, hehe.
• Fourth, the questions asked are some hypothetical questions, assuming that the technical personnel can not communicate. I’ve been told I’ve never seen a situation where I can’t communicate. The results will continue to be asked. So you don’t see what you want, and you make everyone unhappy. A better question: “Can you give me an example of a time when you communicated with someone who was difficult to communicate with?” or, when the candidate says “stand up for yourself”, “Can you give me a time when you stood up for yourself?” .
• Fifth, the whole interview process is all about empty talk, like clouds in the sky, with nothing real at all. Here are two solid questions: “What products have you designed before?” “, “How do you and your technical team work together?”

This is a complete failure of the interview. The interviewer doesn’t know anything about interviewing. Maybe he’s just looking for someone who can go along with him at work.

A Friend’s Interview

Finally, I would like to talk about the interview of my friend, who has strong learning ability and is good at studying. He has solved many difficult and even low-level problems in his work. He has not been doing software development for a long time, but he is very passionate and persistent about the industry, and has quite a good technical background. One day, he met an interviewer who, according to his friend’s description, asked three questions: one about asynchrony, one about performance tuning, and one about learning ability.

• When asked about asynchrony, my friend talked about asynchrony in multithreading, but he probably asked about asynchrony in network or business, or asynchrony in Linux kernel. Of course, he did not make it clear, but he was not satisfied with my friend’s answer and asked my friend to go back and read more books.
• When asked about performance tuning, my friend mentioned three levels of performance tuning, business level, instruction level and CPU level, and cited the use of a performance analysis tool called VTune as an example. The interviewer said that you only knew Windows, which was a little dismissive, and that he only knew how to use business tools, which was even more dismissive.
• When my friend clarified the question to him, the interviewer just shook his head and sighed. And repeatedly interrupting the candidate while he or she is answering.

My view is as follows:

• For asynchrony, I think it’s a design or an idea that can be implemented in many different ways and used in different scenarios. The interviewer didn’t test the candidate’s understanding of asynchronous methods, what they could be used to solve, the advantages and disadvantages of asynchronous methods, etc. I just don’t think the candidate gave the answer he was looking for.
• On the issue of sex tuning, I think the candidates have good ideas and knowledge, as well as experience with VTune. Whether you use Windows or Linux, whether you use commercial or open source profilers, a lot of things are the same, how can you conclude that something is not to your taste? Why not take a page out of VTune’s book? Using tools is just a skill.
• The interviewer should encourage the candidate with a smile, not a shake of the head or a sigh. Frequent interruptions are also a bad habit. It seems that the interviewer is very intolerant of different things.

This person who has great technical skills doesn’t seem to be the right person to be an interviewer, because what he is interviewing for is at the knowledge level, and the interviewer has strong preferences and tendencies, so he is bound to miss the people who are competent but don’t suit his taste.

Ah, in the face of such an interviewer, we can not hurt ah!

(Full text)