Recruitment outside the door

Technical recruitment is also a technical activity. Not only are the applicants seeking for a question, but the interviewer is also racking his brains. In this article, I have reviewed my experience as a candidate and an interviewer, and I will give you a glimpse of the Technical recruitment at home and abroad.

At the beginning of the year, the city of California job unfavorable, the author of the "California job records" (http://blog.liancheng.info/job-hunting-in-California/) an article, the name of the column to see the official love, just two days to hit the tens of thousands. Then, I received an appointment email edited by programmer magazine asking if I could write a record about the similarities and differences between domestic and foreign recruitment based on my past recruitment experience. After graduation, in addition to the three companies Google, Amazon, and Facebook that have attempted at the beginning of the year, the formal recruitment interview for candidates has only joined Baidu many years ago.
That time. In contrast, Baidu has been recruiting for two years, and the experience as an interviewer is much richer. After thinking about it, I decided to write about the recruitment interview Based on my personal experience. It should be noted that some personal experience is described here and it is not universal. The opinions from the interviewer's perspective in this article cannot represent the general characteristics of Baidu and even domestic IT enterprises. Likewise, the opinions as candidates cannot represent the general characteristics of large companies in the Bay Area.

Interviewer's mind

Recruitment interview refers to the communication and recruitment between the interviewer and the applicant. Usually, interviewers take the initiative in the interview. Whether the applicant can pass the interview depends on whether the applicant can prove that he has the qualities required by the organization represented by the interviewer within dozens of minutes. As the saying goes, "Know yourself, know yourself, and know yourself" cannot beat anyone. What do the interviewer think? The quality they want to see can be roughly divided into two categories: hardware and software.

The so-called hard quality refers to the knowledge of basic skills and system structures, operating systems, networks, data mining, distributed systems, and other specialized skills in algorithms, data structures, and programming languages. The reason why hard quality is "hard" is that these quality questions can be obtained immediately, and there is basically no possibility of passing the exam.

The so-called soft quality is something that is hard to judge by ordinary questions, such as learning ability, stress resistance, communication ability, logical thinking ability, and value orientation. Are you familiar with this list?

Many candidates will add the "self-evaluation" column to their resumes, among them, "Excellent learning ability", "good compression ability", "Good communication ability", and "strong logical thinking ability" are listed. I just graduated from college, and I was not vulgar. In fact, these words are also written in White: nothing can prove, empty space occupation, or even reverse effect. It is better to write solid content on your resume. soft quality may be expressed by letter of recommendation or other means at the right time, or you may leave it for the interviewer to check it in person during the interview.

It is not hard to imagine that soft quality is more difficult to measure than hard quality, or even "follow your feelings. Many interviewers are not good at examining soft qualities, especially for beginners. Logical Thinking and communication skills are good to say. During the interview, you can see that your response is not fast enough and your speech is organized. Basically, you can give reliable comments. How can we test this learning ability, stress resistance, and values? To put it bluntly, there are three words: digging details.

It is true that judging a person's soft qualities often requires long-term co-occurrence and observation. However, our final judgment is actually a typical example of this person. Therefore, as long as the candidates can give examples to prove their own soft qualities in the interview, they can achieve the purpose of the study. The authenticity of examples is guaranteed by mining details. If it is a blind compilation experience, most of them will be confused.

When I was an interviewer, I encountered such a negative case. At that time, it was a social recruitment interview and a young man who just got a job. At first, I spoke very well about him. Later, in describing the project experience, he mentioned that he had worked on a set of systems, and I was interested in the experience of similar systems, with great interest, I have successively asked several questions about the system design ideas and implementation details.

I didn't expect a few questions, but he got nervous and suddenly said with a red face: "I'm sorry, I didn't actually do this system, but I made up one to enrich the project experience, but it cannot be compiled ......" At that time, I actually didn't know this method, but it was just a moment of continuous questioning to reveal details. Later, during the school recruitment interview, I learned this trick only from the interviewer training organized by the company, and called it the star interview method, which is dedicated to soft quality inspection, interested readers may wish to search for the latest one.

Brute force attack to obtain the Bay Area

In terms of personal experience, the interview and inspection sites of large companies in the Bay Area are hard, and the interviewer's recruitment is generally strong and powerful. It is really unfeasible to have no hard work such as iron shirts. This is highlighted in programming questions during the interview.

During an interview between forty-five minutes and one hour, according to the speed at which the applicant solves the problem, the interviewer will throw one or three questions. The applicant should not only quickly come up with ideas for solving the problem, complete and error-free code should also be written on paper or whiteboard (via Google Docs, collabedit, and other online collaborative editors during the telephone interview, in rare cases, the applicant is allowed to "say" the Code directly on the phone ). Therefore, candidates with ACM background will have a great advantage.

This requirement is quite strict with most domestic IT companies. However, the interview is not a competition after all. Compared with the difficulty, the differentiation of questions is more critical. Therefore, these programming questions are generally not very difficult and far from ACM/ICPC competition questions. For an inappropriate example, the interview of a large company in the Bay Area is somewhat like a postgraduate entrance exam. It is all the knowledge points in books. It means that the candidates are not well mastered.

During the two interviews at the beginning of the year, I did not use binary_search and partition in the C ++ standard library when solving the problem. So the two interviewers asked me to write the complete implementation of these two functions. These two algorithms are well-known, and they depend on whether you understand them thoroughly and whether the border conditions are handled cleanly. The interview experience at the beginning of the year has been detailed in the California job history, so I will not go into details here.

Of course, the interviews of large companies in the bay area are not just about hard work. The soft quality inspection is generally handled by HR and the special "behavioral interview. In general, however, there are still obvious routines for such soft and qualitative interviews in technical positions of major companies in the Bay Area. Search for "60 behavioral interview questions" on Google to find a tip. What applicants need to do is to clear the background of various project experiences listed in their resumes before the interview, so as to be concise, realistic, and appropriate in the interview, and won the interviewer's favor.

At the beginning, I had objections to the interview style of large companies in the Bay Area. After all, in practice, no one will require you to complete one-time Encoding without using a debugger or other tools. Moreover, the competition-based algorithm question code and industry code are completely two types of routines (ACM players should be very experienced a few years ago in the industry ).

But on the other hand, it is a wise person and a wise person who can reach this level. In addition, this method is right or wrong. It is highly unified and easy to determine. In a large-scale interview, it is more conducive to unifying the interviewer's judgment standards, so as to strictly control the quality of the interview. Of course, its shortcomings are also obvious. For example, the lack of soft quality inspection, the applicant's free use of small space, it is difficult to see the creative side of the applicant. In addition, because the code style of algorithm questions is different from that of Industrial Code, it is difficult for such interviews to judge the performance of candidates in their actual work.

It should be emphasized that at the beginning of the year, I only participated in interviews for general technical positions, and the content I observed was very limited. The above conclusions are based entirely on personal experience, and it is hard to say how many versatility there are.

Just now

On the other hand, when I was worried about recruitment, my colleagues and I were more concerned about soft quality and practical work ability during the interview, especially social recruitment.

We have always believed that, as long as we can meet our basic requirements, it is easier to cultivate and exercise hard qualities such as the technical skills of candidates, however, soft qualities such as communication, learning, logical thinking, and stress resistance are relatively difficult to cultivate. As for the actual work ability, it is certainly because it is hoped that the applicant can join the battle as soon as possible after entry.

In line with this principle, I will generally use the following three methods in the interview.

1. Talk about project experience.

2. Give a simple basic question.

3. Generate more difficult open questions.

For school recruitment interviews, because the project experience of fresh graduates is often relatively thin, there are not many mining points, mainly the second and third types; for social recruitment interviews, the three types are used.

Chatting with past project experiences is a good way to test the soft quality. In this process, we can often capture many typical cases worth in-depth mining. I generally like to ask candidates to pick the most difficult or proud project in their past experiences. In the process of describing a candidate, I will constantly ask the other party to fill in various details, such as the decision-making process behind the key design, what attempts have been made during the difficult process, and what help has been sought, what materials have the team encountered in the project, and so on.

By exploring these problems in depth, the applicant's image will quickly become full. For example, some candidates may make multiple attempts at the design stage, or take the initiative to speak out when they think that the team is going astray. Some people will give up on the principle and follow the rules passively because the above requirement is correct. It is easy to understand.

After talking about the project experience, the applicant's nervousness is also relaxed, then you can take out one or two basic questions to test your skills. The form and function of the basic questions are similar to those used by large companies in the Bay Area, but it is generally not required to write the complete code. It is used to quickly determine the basic competence of candidates and determine the subsequent interview pace and duration.

If you can give answers smoothly, you can proceed to the next step. Otherwise, if the answer given by the applicant is incorrect, or there is still no progress after several prompts, it is not necessary to carry out subsequent interviews.

Progressive open questions are mainly used to evaluate logical thinking and communication skills. These questions are difficult and do not necessarily have the only standard answer. They can be divergent layer by layer. Generally, candidates are not expected to provide a complete answer independently. Obviously, it is necessary to set up obstacles for candidates to solve problems, but the ultimate goal is not to make candidates difficult. This is to check whether the applicant can properly break down the problem in the face of difficult problems, and whether he can find the first problem to be solved in the chaos, can you clearly describe the obstacles that direct your forward, whether you dare to ask questions, and whether you can quickly use the clues in the prompts to overcome the obstacles.

If a candidate is overwhelmed by lack of clues after obtaining the questions, I will explain the intention of such questions to him and encourage him not to worry about having no clue at the moment, although I am bold enough to talk with me about my current ideas and seek help. Therefore, in the study of such questions, the atmosphere tends to be more discussion rather than interview. In this way, the applicant will be more relaxed. As an interviewer, I can more accurately judge the communication and creative thinking abilities of the candidate. After finding the answer, the candidate will also have a sense of accomplishment. In a social recruitment interview, there was a friend who had no background in the distributed system. In this discussion, he summed up the CAP principle, which surprised me very much.

In another campus recruitment, I asked the candidate to improve the automatic client upgrade mechanism in one of his projects. After several rounds of communication, the candidate's ideas surged and soon I drew several more reasonable designs. It turns out that most candidates with similar performance in the interview can become the mainstay.

This set of roads seems to be flexible and smooth, but it also has its fate: that is, the interview standards are too vague and difficult to unify. If the organization is not large, the number of interviewers is small and excellent, I 'd better say. If it is a big company with tens of thousands of employees, it is difficult to guarantee the interview standards for all departments and all interviewers. In Baidu, the entire recruitment process will be supplemented by various process measures and specifications, in order to bridge the individual differences between interviewers as much as possible. This problem cannot be solved, and its harm is very fatal to large-scale centralized recruitment activities such as campus recruitment.

Bole's bet

The last part of the interview is very sensitive, that is, to determine whether the candidate will pass the interview. Which one is a Maxima? This is an eternal gambling game for the happy people. Baidu's interview is based on a five-point system. The interview passes at or above three points, but fails at or below two points. Some interviewers, especially new ones, are more "benevolent". They will always struggle with candidates that fall into the passing line and give a 2.5 score. Once a 2.5-point candidate appears, we will ask the interviewer a question: Do you want to place this person on your team? [Note: Baidu interviews are often conducted by interviewers from different teams. Each interviewer often performs interviews with candidates from other teams .] If the answer is yes, we will arrange another round of interview for further study; otherwise, the interview process will be terminated.

"2.5 candidates" can be divided into two types. The first one is to give people a uncomfortable feeling, or the first impression is not good enough. This is actually a wake-up alert for possible soft quality issues for candidates. If the interviewer does not expect this candidate to join his/her team, most of the other team leaders are unwilling. This judgment seems to be too harsh, but it is a summary of the painful experience behind it.

The other is even more interesting. Although such candidates are generally answering questions, they still want to give them a chance. I have encountered such a case. At that time, I was a two-way interviewer, who was very entangled and finally gave the interview Result 2.5. I asked him, give it to you, do you want? I didn't expect him to say "yes" without hesitation, so I decided to face the candidate. I was very impressed by the fact that the candidate was quite young and had tattoos on both sides. However, during the interview, I found that this interview was very enthusiastic about the technology, very energetic, and flexible. In fact, he is the candidate who independently summarized the CAP principle during the subsequent interview. Later, this "2.5 candidate" was not disappointing, and it quickly became the backbone. Therefore, the interview is a matter of luck for both candidates and interviewers.

There seems to be a lot of summary on the two roles at the same time. I hope that my one-sided experience will give you some inspiration and help.

Lian Cheng, former Baidu senior engineer, technical translator, function language and distributed system enthusiast.