Xueba, I beg you to go and escort him quickly!

next second.

Xu Heng appeared.

"Master Red."

clap la la...

suddenly!

Hong Jingjun suddenly raised his head and wanted to get off the car immediately, "Xu Heng! Why are you here...!!!"

There is a feeling of "there is no place to find when you break through the iron shoes, and it takes no effort to get it".

Xu Heng, "Don't, don't, we get in the car, you don't want to get off."

Hong Jingjun asked the driver to unlock the car door, and he immediately moved places for Xu Heng and Yue Pingting!

The three of them sat in the back, Hong Jingjun sat on the far left, Xu Heng sat in the middle, and Yue Pingting sat on the left and right.

She greeted people when she saw them, and didn't care about anything else, just swiping her phone.

The Red King Army is very excited!

He looked at Xu Heng and smiled from ear to ear.

"I've said it all, don't let them in! They really don't believe it! What a bunch of blind guys!"

"Driver... We are in the city, so we are looking for a teahouse with a better environment."

Not even going to the county!

Go straight to the city!

The group of people in the research institute was completely ignored.

Hong Jingjun, "They don't even have the most basic attitude! Hey...all of them are eager for quick success!"

"Student Xu Heng, don't be surprised, and don't think that the impetuousness of the Institute of Mathematics is actually because you are too amazing to scare them!"

"A high school student can prove all kinds of theories in the mathematics world! And with a brand-new proof idea and process, this is tantamount to discovering a new world for them!"

"Actually, their eagerness is understandable..."

The Red King Army is telling Xu Heng to calm down and not to be angry.

"In their shoes, you might as well."

Xu Heng smiled.

"Old Hong, don't tell me this! Why do you care about them? Isn't it?"

"You took me to the city, and I know your position."

"You're also respecting my position."

"But... Then again, I thought you had entered school before, and even you were scolded."

Xu Heng was not afraid of Hongjing Army getting angry.

Because everyone is like this!

What can be angry?

On the contrary, Hong Jingjun laughed loudly, "You little guy is not shy, you really have a temper!"

They chatted for a while, and Hong Jingjun got down to business.

"Xu Heng, apart from proving the equation between the 0.999 cycle and 1, can you prove anything else?"

"Or... would you like to try it?"

The corner of Xu Heng's mouth was drawn, "Not yet! Hong Lao, don't ask! Right now, I think I have enough trouble!"

"I don't want to cause me more trouble!"

Hong Jingjun hesitated to speak, "All right! All right! But if you believe me, you little guy, you can talk to me more about these things."

The corner of Xu Heng's mouth was drawn, "Old Hong, if I don't believe it, why should I get in your car!"

Hong Jingjun was speechless, then smiled.

The atmosphere in the car is lively.

After arriving in the city, they found a place with an excellent environment.

Enter the private room.

Hong Jingjun ordered a pot of tea several thousand in size, and they sat down.

Xu Heng looked at the Hong Jingjun who was slapping his face, and there was no disturbance in his heart.

Yue Pingting, on the other hand, widened her eyes and covered her mouth, "Oh my God! Thousands of dollars, is it a big bucket? Or how much! It's too expensive!"

Xu Heng rolled his eyes, "You girl, that's too much."

Yue Pingting curled her lips and said helplessly, "What I said is the truth!"

Hong Jingjun smiled and said, "I think entertaining classmate Xu Heng is still far from enough."

Yue Pingting couldn't help giving a thumbs up.

Hong Jingjun is still smiling.

Xu Heng rolled his eyes at Yue Pingting again, and looked at Hong Jingjun, "Master Hong, don't be as familiar with this girl, she is just like that."

Hong Jingjun, "Eh...so...what do you mean...?"

Xu Heng, "No no no! Nothing, just kidding! Just kidding."

For a while, the Hongjing army didn't know how to try it.

Believe it or not?

For the first time, the Hongjing army had a difficult time.

But it was passed by Xu Heng.

In such an environment, Yue Pingting picked up her mobile phone, and she did not participate in the discussions and chats between the two.

Xu Heng chatted a lot with Hong Jingjun.

Starting from 0.999 cycle equal to 1, we talked about a lot of problems.

It also involves NP-complete problems.

"Student Xu Heng, you should know about NP-complete problems, one of the world's seven major mathematical problems!"

Heng Xu, "Nondeterministic Problems of Polynomial Complexity."

As he said that, Xu Heng wrote down on the paper prepared by Hongjingjun: NP=P?

The problem lies in this question mark, is NP equal to P, or is NP not equal to P?

Hong Jingjun nodded, "In layman's terms, some calculation problems are deterministic, such as addition, subtraction, multiplication, and division. You only need to follow the formula to deduce it step by step, and you can get the result. However, some problems cannot be solved. Calculated step by step and directly."

"Generally, such problems that cannot be calculated step by step can only be solved by violent methods such as the exhaustive method."

Xu Heng drank his tea and said, "There is a classic example, right?"

Hong Jingjun seemed to have found a bosom friend, clapping his hands and exclaiming, "That's right! The traveling salesman question."

"Suppose you are a traveling salesman and you need to travel to 5 different cities. Of course, you want to find the shortest route to these 5 cities. To do this, you must calculate every possible route and compare them one by one."

"Then I have to consider a question here, how many possible routes are there to go to the 5 cities?"

"To solve this problem, we first consider the situation with only two cities, and then increase the number of cities in turn."

Hong Jingjun drew while talking.

"There may be a little controversy here, that is, in theory, going from A to B should be the same as going from B to A, but in practice, there are often one-way streets, so here we think that going from A to B and from B to A should be the same. B to A is different."

"So, when two cities are involved, there are two possible routes."

"After that, there are three cities..."

"Four cities..."

"So, in order to find the optimal route for these 5 cities, we need to traverse all possible routes, and then compare them one by one to obtain the optimal route!"

Yue Pingting glanced once in a while, wondering, "This doesn't seem like a difficult question, does it?"

Xu Heng rolled his eyes at Yue Pingting and asked, "What about 10 cities?"

"It just needs more than 300 million roads..."

"So, you need to calculate all the solutions and choose the smallest or shortest one. To do this, you have to go through all the possibilities and compare them one by one."

"The traveling salesman problem is a classic NP-complete problem."

Hong Jingjun looked at Xu Heng and nodded with satisfaction.

It seems that Xu Heng is well versed in this...

Here, he and Xu Heng talked freely and had a lot of fun.

But in Yunshan County, the headmaster was treated coldly by everyone, which was really uncomfortable.

"How many times have you asked me to say it! I really don't know where Xu Heng has gone!"

But they don't believe it!

Because someone said that Xu Heng was in his office...

Chapter 306

Xu Heng chatted with Hong Jingjun for a long time.

The two were talking and laughing.

It was already past nine o'clock in the evening when he was sent back.

Xu Heng didn't know how the school dealt with it, but they all left, including the leaders of the Provincial Education Bureau and the teachers from the 24 schools who came to attend classes.

The principal was in the principal's office and never came home.

When the guard called to say that Xu Heng was back, he rushed to the school gate.

Xu Heng got off the car.

Yue Pingting got off the car.

The Hongjing Army also got out of the car.

The principal was very excited, and he was relieved to see Xu Heng and Yue Pingting come back~.

Looking at Hong Lao again, he immediately cleared up his bad mood and greeted Hong Jingjun.

"Old Hong, hello..."

Hong Jingjun looked at the principal. In the afternoon, he heard Xu Heng talk about this principal who "takes good care of him".

and so……

Hong Jingjun patted the principal on the shoulder, "Little guy! Don't hold back! Don't worry! No matter how the group of people who came today threaten you, tell you, or yell at you, I am there!"

In the eyes of Hong Jingjun, the principal is indeed a little guy!

"Let's take a step back and say, if there is no me, there will be Xu Heng!"

"Let me tell you the truth, with Xu Heng here, even if the sky falls, it's fine!"

"Do not worry!"

The Hongjing army got into the car and left.

The principal sighed, "Thank you, Mr. Hong!"

Turning around, the principal looked at Xu Heng seriously, "Thank you too, Xu Heng!"

Xu Heng looked at the principal, and he also said "thank you".

The principal's nose was slightly sore, and he almost froze.

"Huh... this day is probably a nightmare for me, and for our entire Yunshan High School!"