“The Russians were right to decide to walk on two legs,” Raphael said. “As long as you understand a little bit, you can figure out that autonomous heavy equipment and autonomous humanoid units can find corresponding positions in the army system and can be integrated quickly.”

She took out the cup, walked to the side and made two cups of instant coffee, then said:

“But one thing is clear: when the autonomous system emerges, the development of another thing, that is, targeted electromagnetic pulse weapons, will enter a new fast lane.”

When Lingyin heard Raphael say this, she immediately thought of her previous personal experience, so she blurted out:

“EMP electromagnetic pulse attack.”

Raphael asked with an inexplicable smile: “Smart Lingyin, please tell me, what is the best electromagnetic pulse generator currently?”

“nuclear weapon.”

“Yes, at that time, the battlefield will return to tradition.”

“What tradition?”

“The fighting between people is aimed at destroying the flesh.”

Chapter 231 Pascal’s Ambitions

In fact, what Raphael wants to do now is not to wait for the war to break out, but to enter the Soviet territory with a humanoid team and sufficient equipment support to find and kill the contact person sent by the Beacon of the Relics Bureau in the Soviet Union.

But this plan is tantamount to suicide.

But now is not a good time to think about these things, about 27 people are sitting in the classroom waiting for her to feed them knowledge.

Raphael turned around and put down the blackboard. He wrote down two sequences: X{A, B, C, B, D, A, B}; Y{B, C, D, A, B, A}, and asked:

“What is the longest common subsequence of sequences X and Y? See if you can figure it out with your naked eyes.”

She looked around and heard someone answer “AB” and then pointed to the sequence and said:

“AB, is the length only 2? Has anyone found a longer one? Don’t be shy, speak up.”

“DBD, BDAB”

“anything else?”

Raphael pointed to the longest “BDAB” sequence and wrote it out, saying:

“So BDAB is the longest one.”

She habitually tapped the longest common subsequence she had written with chalk, and then asked the students in the lecture hall:

“Is there any that is the same length? Is there any that is comparable to it?”

“BCAB!”

“Any more?”

“BCBA, great, these are length 4.”

Finally, a student dared to respond loudly. Raphael slowly exhaled and said:

“Okay, now let’s use the algorithm to prove that what we have visually verified above is correct and that there is really no common subsequence of length 5.”

As she wrote on the blackboard, she said:

“For these subsequences, we can say that the LCS of any x and y, here we prefer to use function symbols, that is, LCS(x, y), but in essence it is a relationship rather than a function.

So, we call this LCS, referring to one of those LCSs.

Of course, this representation is not very standard. But as long as we know it, it is not a big problem. Also, we should not use symbols randomly, but it is also good to be a little casual, because simpler representation is more conducive to expression.

The premise is that you understand what its essence is.

So, let’s continue. This problem can be solved by exhaustive search, which is to check every – maybe you just thought of it this way – every subsequence from 1 to m in x, and then see if there is the same subsequence in y, that is, to calculate all the subsequences in it. “

Algorithm courses are so boring, but anyone who wants to make a name for themselves in the computer field cannot escape the torture of algorithms.

Raphael stood on tiptoe and pushed the blackboard up.

This adorable look of struggling made the young people sitting in the front row couldn’t help laughing.

“Okay, focus.”

Raphael coughed and continued:

“Analyze this operation. If you know a subsequence of x, how much time do you need to spend to determine whether it is a subsequence of y? For example, if I give you a sequence like BCAB, is it a sequence of y?”

“The length of y is O(N).”

“How did you know?”

“Just scan it.”

“Yes, if the first identical character is found, then recursion starts according to the table below x and y to determine whether the corresponding elements in x and y are the same.

In short, just go through the string and see if there are any similarities. “

Raphael glanced at the teaching plan information in his hand and asked the second question:

“So the second question naturally becomes, how many subsequences does x have? 2^m?”

“x is from 1 to m, which means there are 2^m subsequences of x.”

The answer to the second question was still given by the same student, which made her feel a little unhappy.

“Well, you are right. There are 2^m subsequences of x. We have a way to count how many subsequences of a sequence there are. Consider a ‘bit vector’ of length m, which is actually a binary number with 1 and 0 representing the elements on the corresponding bits.

The elements on each bit are only 0 or 1. If there is an element marked as 1, it means that this element is put into the subsequence by me, so that I can get a mapping.

Of course, some subsequences may have the same characters, but that is the worst case, when all characters are different. In that case, each subsequence is different.

So each bit vector of length m corresponds to a subsequence. The general idea is this, so the running time of this method under the worst conditions is O(n·2^m), that is, since m is in the exponential position, the running time is also exponential.

Here, we can use a term to describe exponential running time, which is slow. “

Raphael’s words were full of confidence and affirmation. The students who were watching the class through the clear blackboard writing couldn’t help but sigh in admiration.

She glanced at her watch and said loudly:

“Take a 10-minute break. If you have any questions, you can come up and ask them now.”

Obviously, none of the students in the seats had any intention of getting up, because this was just the worst and most inefficient way of calculating, and any student who passed the C/C++ course exam could use this method.

What follows is the key.

Raphael knew this very well. The core of this class is dynamic programming. She will show a more efficient solution in the following time. The case of the longest common subsequence is a classic case of dynamic programming, and then explore the consistency of recursion and dynamic programming.

She believes that understanding and comprehension are not the true mastery. Only by savoring the details and having one’s own unique insights and feelings can one be said to have learned the knowledge to the depths of the soul.

Raphael unscrewed the kettle, took two gulps, then moved closer to Pascal in the corner of the front row and said in a low voice:

“Why didn’t you go to Rhein Frankfurt? I heard the academic atmosphere there is also very good.”

Pascal lay on the long table and answered in a muffled voice:

“I’m not stupid. The traditional computer science subjects there are indeed strong, but the artificial intelligence here should be the strongest… Why bother to go far away?”

“How’s the atmosphere in the lab? I hope those brats didn’t give you any trouble.”

“No.”

Pascal pursed her lips. This was completely different from the laboratory she had imagined.

I’ve heard before that there are some rubbish professors who don’t treat students as students. Not only do they want students to work like slaves for them, they also try to steal students’ research results.

In addition, it is possible to force graduation to be postponed because of the ease with which you use the technology.

But Raphael’s laboratory is completely different. The manager of that laboratory seems to have seen through the world, and the status of other team members is not much different.

Here, except for the laboratory project team members whose mental state is a bit bad, it seems that only the senior brother has been stuck in graduation, and the academic levels of the rest of the people are on normal track.

She recalled how the senior brother answered the questions effortlessly when she had repeatedly tortured him with entry-level questions. This made her immediately understand why the senior brother’s graduation was delayed – it was too easy for him to do so, and she was reluctant to let him go.

However, the junior from the Automation Department named… Pascal thought for a while, oh, the junior named “Lecco Reese” – who was rarely recruited into the laboratory in his sophomore year – was in a slightly better mental state.

What made her feel even more strange was why Raphael would recruit such a young automation student.

However, Raphael’s willingness to recruit him shows that she is optimistic about his talent and ability. After all, she doesn’t want to keep idle people.

I just don’t know what my junior will choose in two years, whether to stay in the laboratory to pursue a degree in artificial intelligence, or leave and return to his old career and seek further study with a professor in the Department of Automation.

Actually, both are acceptable. This major itself is a hodgepodge of multidisciplinary subjects, commonly known as a “jack of all trades”, which basically includes many core courses in the direction of computing.

In addition to automatic control theory, the course also teaches hardware knowledge and software programming, which are actually the basics of computers.

If you want to apply for a doctorate under Raphael, it should not be very difficult if you are already promising.

Some people used to doubt Raphael’s ability, but as the artificial intelligence laboratory continued to obtain military projects and produced continuous results, no one questioned Raphael’s ability anymore.

Those who were interested began to eye the position of Raphael’s direct disciple.

Now that I have the title of professor, it has even more significance and the treatment is extraordinary.

Just like the leading authorities in other industries, every move he makes is very eye-catching.

Some of the choices are even more intriguing. Since Raphael has opened up the quota, everyone is thinking about it.

Pascal secretly observed Raphael out of the corner of his eye. He had guessed that she must be very powerful, but what was even more amazing was that Raphael’s height and development level seemed to have not changed over the years.

Raphael rolled up the lesson plan, tapped the girl’s forehead gently, and said sinisterly:

“My intuition warns me that you are thinking of something strange and impolite right now.”

“Where’s the evidence?” the girl said with a smile, tilting her head.

“You will help me operate the blackboard later.” Raphael turned his head and said, “Don’t refuse.”

As the blackboard was pulled down, the students’ respectful eyes were all focused on Pascal.

There, they seemed to see the future of their dreams, and the whole classroom was suddenly filled with a passion for striving for progress that left Pascal puzzled.

“Okay, let’s look at a new approach. Of course, this will be divided into several steps…”

With a crisp sound, the chalk tip could no longer withstand the pain of Raphael’s strong finger strength and the friction of the blackboard, and broke off cleanly.

“Well… the first step is to simplify. Let’s see how long the longest common subsequence of x and y is.

Based on this, what we need to do is to expand this algorithm so that it can find the longest common subsequence.

Starting from the length of the sequence, we should first try to simplify the problem of calculating the length of the LCS, which is pleasantly unique. “

As the course progressed, Pascal found that Raphael’s teaching speed was getting faster and faster. The content written on the blackboard was one after another, from simple to difficult, step by step, going deeper and deeper and leading students to think along her lines.

So, as soon as Pascal finished erasing the writing on one of the blackboards, Raphael came over with a piece of chalk and asked her to deal with the outdated writing on the other blackboard.

An hour later, Raphael said to the students present:

“Everyone, what I showed you today is by no means just theory. As long as you can understand today’s content, implement it with code and conduct careful analysis, I believe you will soon be able to master it and gradually apply it to your actual life and work.

Algorithms are a field that requires skills and creativity. I hope you can also aim to become experts and scholars in the field of computer science and strive for this ideal. “

After saying that, Raphael threw the white chalk aside and announced:

“That’s all for today. Go to the teaching assistant to pick up your homework after class. Don’t forget to submit it. And remember, if it’s judged as plagiarism, I will have to ask you to leave my class list.”

The students were still immersed in Raphael’s wonderful presentation, sitting in their chairs in ecstasy.

“Pascal, follow me.”

“Oh.”

The girl clapped her hands hurriedly, picked up her personal belongings on the seat and trotted after him.

After leaving the classroom, Raphael put away the smile on his face and walked indifferently on the road towards the laboratory.

After entering the office, she could finally take a breath. She started in the morning with two algorithm classes at different paces, and in the afternoon she had to hold a group meeting to check the progress of several projects in the laboratory.

We should also pay attention to Willy Adenauer’s mental state, so as to prevent his founding disciple from causing trouble for himself.

In the evening, I went to MfS to find Hans Schmidt and discussed with him the development and application of strong artificial intelligence in the command system, and learned more about their needs and main application scenarios.

She took off her coat and lay on her back on the sofa, her face showing an expression of being numbed by the overwhelming pressure.

At this time, Pascal walked in.

“Sister Raphael, the college office just called and asked you to find time to go there after class and before get off work.”

“What? You want me to go to the college office?”

The first thing Raphael thought of was his previous attempt to hand over the financial power of the laboratory to the chief economist, and the people in the hospital came to question him.

“Okay, I’ll go over now.” Raphael said, and then he took out two lists from the locked cabinet, stuffed them directly into Pascal’s arms and said, “Read everything on them before June next year.”