Why do programmers ask for "building rockets" during interviews?

First,? Test the solidity of mastering professional knowledge.

There is a question in Zhang Xinxu's Ten Questions and Ten Answers: "What is the standard of solid foundation for front-end development? I think his explanation of "solid" is very suitable for answering this question. In fact, "tie" can be understood as depth. You can imagine sticking a needle into your skin, and the pressure at a point will make you uncomfortable.

So how to understand the depth of knowledge?

I'll take the front-end interview as an example. Take a quick ranking test, for example. Many people think it's nothing to test, but it's usually useless. The sorting method has been written at the bottom of the engine, and the sorting order used at the bottom has been realized. There is no need to test. But the interviewer doesn't really want to test how you write fast-paced code. To tell the truth, you can definitely remember a fast-paced code in ten minutes, at most half an hour. But in fact, the real reason for fast scheduling may be not only the code, but also its idea, divide and conquer (the method of divide and conquer) and the application of partition algorithm.

In addition, you may be asked what its time complexity is and how to calculate it. These questions are not to test the calculation of your algorithm, but to see if you know how to calculate the time complexity through this algorithm. This will guide you why the sorting is fast and why the merging sorting is not so fast. And so on.

The interviewer's question is only an application of various bottom-level ideas, and this example is used to investigate the understanding of the bottom-level ideas. Therefore, many times, big factory interviews always ask questions from shallow to deep until you don't know.

Let's talk about "reality". In fact, it can be understood as fullness, and the breadth of knowledge can be examined.

Imagine what you would say, give you rice all night, and press it, and put some more rice in it until it can't be pressed down. At this time, you will say that you have a full night's meal, which is very true. Therefore, the understanding of "truth" can be understood as fullness and completeness.

How to reflect your knowledge, that is, reality.

For example, you can examine some knowledge points that are not usually used, but may be used. Such as some simple algorithms and data structures, linked lists, and those in the network? tcp/ip？ Protocol family, functional programming, etc. , some html5? Characteristics (such as? We b-component) and so on.

You may not use it in your usual programming, or most front-end engineers don't use it at ordinary times, but these are the basic skills you need to know, such as? Reaction? Some simple data structures are used in the source code. The linked list tree is stored in the linked list structure, which is a single linked list with a circular linked list. If you don't know that a tree can be stored in a linked list and how to operate the linked list, then you may have a problem reading the source code. There are some bit operations and so on. Bit operations are not commonly used, are they? fb？ Engineers use it to solve practical problems.

Another example? Web component, which is already? w3c？ Put forward a front-end component standard, which is also widely used in China? Web component? Implemented some libraries, such as Tencent? OMI .

Our front end is changing rapidly, and there are many new things. How can we not keep pace with the times and learn more about new things (mainly because we don't have to delve into everything new, because you don't have that much time, and most of the time we have to spend where we usually need it). If you can't keep up with the times, you will be gradually eliminated, so now front-end recruitment basically requires you to understand a framework, right? Reaction? , Vue, Angular, these are trends, data-driven, not picked up before? jQuery？ It is dry.

The knowledge points commonly used in work are the most important, so everyone understands them. If you don't know what others don't know, and these things are more profound than others, why does the interviewer want you?