"Discrete mathematics is a mathematical discipline that studies the structure of discrete quantities and their interrelationships, and discrete mathematics can also be said to be the basic core discipline of computer science, and discrete mathematics is a bridge between mathematics and computer science."

These two sentences are the explanations of "Discrete Mathematics" that Xing Conglian just found, and he read them out loud, and then was interrupted by the dynasty.

"I'm familiar with discrete mathematics, boss, why do you still have Baidu, look down on me!"

"Then may I ask Wang Xiansen, why did Jin Xiaoan look at "Discrete Mathematics" on the bookshelf when Fu Hao mentioned 'Jiang Liu'?"

"How do you know she's watching Discrete Mathematics! Or maybe it's the book next to it, "A Qiē Starts with Meeting"? Wang Chao asked rhetorically.

"Because in our Wang Shishi's dormitory, we also found the same book of "Discrete Mathematics" belonging to Xu Haozhen......"

"Shenma?" The dynasty snorted, "Unbelievable!" ”

"Speak well!" The torturer slapped the young man's head.

"Damn, "Discrete Mathematics" is not advanced mathematics, it is not a compulsory course in college, and they are not from the Department of Mathematics or Computer Science, why are they suddenly interested in this?"

Listening to the dynasty's chatter in his ear, Lin Chen lowered his head and looked at Professor Fu who was talking awkwardly with Jin Xiaoan on the screen, what they said in the conference room was probably through the microphone, and all of them fell into Fu Hao's ears, so Professor Fu's facial muscles were stiff now, as if he didn't know how to take it.

Professor Fu ...... Do you guess, on the title page of Jin Xiaoan's book "Discrete Mathematics", will Jiang Liu's name be written? He said this to the microphone, and then it was obvious that in the picture, Fu Hao was obviously trembling because of his words.

However, the only way to verify the guess is to do it.

This time, he didn't embarrass Fu Hao again, but said: "Didn't you hold a bag of Wen Jiàn under your armpit, hold a cigarette case with your other hand, pretend to read the book "Yi Qiē Begins with Encounter", and then pretend to be careless and pull out the discrete mathematics as well." Fu Hao probably could only exert his usual 0.1% speech ability when facing girls again, so he continued to instruct, "You can say to Jin Xiaoan: 'You can also read it, I have also read this mystery novel.'" ’”

In short, although the level of the director is not high. But fortunately, Fu Hao acted in an embarrassing nature from beginning to end, so whether it was his introduction or the next action of taking the book off the shelf, it was surprisingly not abrupt.

Several books fell to the ground, Fu Hao hurriedly squatted down, blocking Jin Xiaoan's sight, he first put a certain reasoning book back on the table, and muttered in his mouth: "This book is really good, have you finished reading it?" ”

Then, pretending to be inadvertent, he quickly flipped through the book of "Discrete Mathematics", and did not forget to hold the cigarette case in the other hand, and filmed the process of flipping through the whole book, with a very dedicated attitude.

"Is this book of "Discrete Mathematics" the same as Wang Shishi's book?" Dynasty manually slowed down the screen, dragged the progress bar forward, and asked.

"Same." Lin Chen stretched out his finger and lightly drew a circle on the screen.

In the lower right corner of the title page of the book, the name "Jiang Liu" really appeared.

"Take a picture of the copyright page, and then you can retreat." After Lin Chen finished speaking, he turned off the microphone.

The conference room was quiet, Lin Chen didn't speak, the torture servant didn't speak, and even Captain Jiang, who was usually very arrogant, didn't dare to speak.

Therefore, the only one who dares to speak up in this situation is the dynasty.

"Is this a sorority, and they still have to send books to each other to urge them to study hard?"

The young man's voice was soft and sweet, although this question didn't have much effect, but just listening to the voice of the dynasty would make people inexplicably relaxed.

"Can you explain a little bit about discrete math?" Lin Chen asked.

"I can't explain it to you, it's too big, too much content, and it's too difficult for you." Although this sentence was to the effect of saying "You mortals have too low IQ", Wang Chao's eyes were so sincere that people didn't even have the strength to knock him on the head.

While they were talking, Xing Conglian followed Fu Hao very seriously to read the original discrete mathematics, and suddenly spoke: "It's a little strange." ”

"How?"

"You see, this book has been turned a little old, but there is no mark on it......" Sentence Conglian pointed to the curly corner of the book and said, "The book that Xu Haozhen gave to Wang Shishi is the same situation, although it has been turned over many times, but there are no obvious reading notes on the book. ”

"What's wrong with no notes, this kind of book can't stand it if a normal person reads 10 pages?" Dynasty said.

"Then may I ask Wang Xiansen, why do you want to turn a book that a normal person can't stand reading for 10 pages to rotten?" The torturer hooked Wang Dynasty's neck and asked with a smile.

At that moment, the little comrade of the dynasty had a flash of inspiration, and turned to Lin Chen and said, "Ah Chen, the boss asked you!" ”

Lin Chen was amused by him, and the original foggy situation suddenly became clear: "The book has been turned over, which can only prove that someone has turned it many times, but not anything else. ”

"What can't be proven?"

"I can't prove it, whether it's Jin Xiao'an or Wang Shishi, they have read this book seriously......" Lin Chen glanced at Xing Conglian, and said, "A professional book like this, most people who read it carefully will take notes on the book while reading it......

"But it's also possible that this book is so precious to them that they can't afford to paint it!"

Seeing that the dynasty would draw inferences, Lin Chen nodded with satisfaction and said: "This is indeed the case, so there are two possibilities now, first, they haven't read the book "Discrete Mathematics" seriously, but simply turned the book over and over again, so what this subject is talking about actually doesn't mean anything to them." Second, they studied Discrete Mathematics seriously because they cherished it too much and did not take any notes on it...... Which do you think is more likely? ”

Wang Chao scratched his head: "I don't know! But to be honest, people who are not majoring in mathematics or computer science have too hard to learn Discrete Mathematics, and the founders of set theory are crazy......"

"So you agree with point one?" Lin Chen interrupted the young man's words.

"Ah Chen, I think you're right!" Wang Dynasty said to him spinelessly, "So the answer is really that they don't understand the farts and flip through the books blindly?" ”

"yes."

"But how do you know?"

"Oh, because you just showed me Jin Xiaoan's file, which contains her college transcript, and she failed in high mathematics." Lin Chen said.

As soon as he heard this, the little comrade of the dynasty quickly took a breath of cool air, and then said to him very sadly: "Ah Chen, don't learn from the boss, this is not good......

"Careful care is very important in the process of handling cases." "And having studied discrete mathematics has nothing to show off." ”

"But why, are they practicing some kind of qigong, flipping through the book and revealing its meaning?" Wang Chao asked depressedly.

"If you add several other keywords in this case, such as 'dark network' and 'poison', do you have any associations about this?" The convict continued to ask.

In an instant, Wang Dynasty's eyes changed: "Damn, boss, I'm going to be creepy, what do you want to do at night!" ”

As soon as the boy said this, the whole room fell into an unbearable silence.

Lin Chen's right hand clenched, and he also fell silent.

A rotten book, a group of college students, a controlled group, a dark webcast, a drug trade, a jewelry robbery, ......

If you connect these keywords in series, it is roughly like this: someone has used some means to sue a group of college students, not only using them to conduct various online live broadcasts to make huge profits, but may even be involved in hundreds of millions of dollars in jewelry robbery and transnational drug cases, and the only clue they have now is that each of these students seems to have a strange copy of "Discrete Mathematics" in their hands.

Then, the role of this book seems obvious.

"What the hell is going on, I find that you don't like to tell the truth." Jiang Chao finally couldn't help but break the silence that was too tacit.

"Let's put it this way, why did the murderer behind the scenes use the dark webcast?" Wang Dynasty asked rhetorically.

"In order not to be found!"

"That's right, whether it's an onion server or a dark network, it's essentially to protect personal services, in other words, it's an encryption method, so if someone accuses a large group of students, does he need to give instructions to these children, then, he also has to ensure that the information he transmits has a certain amount of security, right??"

"No, do you think that book is a code book, what age is it, you still play with this kind of thing, and the relics of the other dead have not found this book?" Jiang Chao reacted quickly and continued: "And don't they have some dark network, so isn't it more convenient to have a dark forum or something on the Internet?" ”

"Oh, it's very simple, isn't this important thing recycled before it dies, is the criminal organization stupid, can such an obvious clue be kept for you to check? It is estimated that Wang Shishi's book must have been destroyed for some special reasons! And in fact, this encryption method, although very simple, is actually quite effective and hidden. First of all, even if you are a roommate, few people will look through a book like "Discrete Mathematics", and it is quite easy to arouse suspicion when you look at a strange page on the Internet in your dorm room. Then, group text messages WeChat or something are easier to be traced, and math books, it has many formulas, and there are many strange characters, for example, I report a number 1612, you know what I said is 16 pages and 12 lines, or 1 page 6 lines and 12 words, if that word happens to be a minus sign, do you know that it means backspace, carry or delete the word? Of course, theoretically this encryption method can be cracked, but it requires a lot of numbers and arithmetic analysis, so the math book can really be used as an ideal password manual...... The reason I think it's ideal is because, who the but my boss would associate a good book with underground cryptography work! ”

"I'm praising you for me." The torturer Lian said coldly.

Finally, Team Leader Ren, who had been hiding in the corner, suddenly became interested in this topic. But it's not so much an interest as it is a question that in itself is his primary concern: "You mean, they use this Discrete Math as an encrypted manual for conveying information?" I think the reason why you can think of this is probably because this encryption method is an underground criminal organization, to be precise, it is a very popular method used by drug dealers, so I can doubt that these students are actually secretly used to deliver drugs? ”

"You can be suspicious like that, but such suspicions are basically useless now." The torture servant said unusually coldly.

"You can't stop my investigation just because of your case!"

"I seem to have said that everything related to Fang Zhiming's drug factory case is not in the general direction of our investigation for the time being?"

"This is a heavy clue, we can follow it down!" Ren Xian raised his voice violently.

"Oh, did the team leader intercept any passwords?" The torture slave company still looked not salty or light, but with a word, Ren Xian choked so much that he couldn't speak.

"Not yet, but I can look back at the archives and maybe there will be a clue......"

"Okay, if you are lucky enough to intercept a password, and then your conclusion is verified, that someone manipulated a group of students to carry out countless illegal and criminal activities, including using them to sell drugs, then what can you use to catch the murderers behind the scenes or save these children?" The torturer's voice was very cold, he stretched out his hand, pointed to Wang Dynasty's laptop, and the picture was fixed on the girl in the seat who bowed her head slightly, "You still don't understand, what is the difference between this case and the murder cases we encountered before?" ”

"I ......" he stopped talking, obviously not thinking about the problem.

"What's the difference?" Jiang Chao also interjected.

Lin Chen looked at the captain of the criminal police who was obviously angry with the two, and couldn't help but pat the back of his hand and explain for him: "The difference is that in ordinary homicide cases, we just need to find the murderer, but in this case, even finding the mastermind behind the scenes is not the most important thing." ”

"Isn't it important to catch the mastermind?"

"Compared with the imminent bloodshed and a group of □□ college students, who is behind the scenes, and what he did with these students, these questions are not important, how to solve the current problem is the most important."

After Lin Chen finished speaking, he looked at Xing Conglian again.

In fact, if he hadn't personally explained the sentence to the company, he would not have found that the original line of thought had always been very clear, the priorities, and the first, he couldn't have judged more correctly.

It was so correct that he had nothing to say.

"Isn't it the quickest solution to find the killer and stop him?" Jiang Chao asked again.

"We now have two threads available, a book and a person. Suppose that discrete mathematics is really a cipher table, but now, we haven't even intercepted the corresponding cipher, this clue is basically useless now, and Jin Xiaoan ...... You didn't pry Cheng Weiwei's mouth open that day, so when you see Jin Xiaoan today, do you think you can pry her mouth open and get any useful information? Lin Chen continued.

"Aren't we still dead now?" Wang Chao raised his hand sadly and asked.

"Who said that?" Xing Conglian lifted the ears of the dynasty and said, "First compare whether Wang Shishi's discrete mathematics and Jiang Liu are determined to be the same version, and then check the copyright page to find the publishing house to see the print run and delivery records, and see how many books have flowed to Hongjing, do you still want me to teach you this kind of thing?" ”

"This kind of trivial thing is wrapped around me......" Wang Chao patted his chest, his hands flying, "first look at the version!" He said, zooming in on the previous picture of the copyright page, and said, "Congratulations, this book was first printed in 2001 with a print run of 5,000, which means that it is really an antique!" ”

"The good thing about the old book is that it may not have been sold online again...... "The boy knocked back and sighed, "Bingo, I really haven't sold it online, I don't know how to evaluate your luck this gentleman." ”

"So, is it good luck or bad luck?" The torturer asked boredly.

"I haven't sold it online, which means that it is through the channel of the publishing house, the advantage is that I can check the publisher's outbound records, the disadvantage is that the time period is too long, it is likely that there are many dealers who have ordered this book in different batches, and any system can only find the first-level dealer, not the second-level dealer, so ......"

The boy jerked back in the epida.

Although he made a lot of assumptions, after he set the search conditions, after the search, only the name of one dealer appeared in the entire Yongchuan City.

【Yongchuan Siyuan Inspirational Book Distribution Co., Ltd. Key Chang Wei 139XXXXXXXX】

At this time, Jiang Chao also handed the mobile phone picture to the dynasty.

The boy glanced at the photo, quickly copied the address of the bookstore, and sent it to his boss: "The two books are the same version, the address is sent to your mobile phone, boss, you can go, byebye!" ”

The time was 8:31 p.m.

Lin Chen first looked at the time displayed on Xing Conglian's mobile phone, and then looked at the address, he found that the location of the distributor happened to be in the book market of Yongchuan University, so he said: "Phoenix Book City usually closes at nine o'clock in the evening, and if you open a little faster, you should be able to catch up." ”

The criminal conglian had already turned around and was about to go out, and when he heard his words, he turned around suddenly and said to Ren Xian: "It's nine o'clock, so the jet lag party on the other side of the ocean is probably about to get up, please keep an eye on Team Leader Ren, if there is anything on the Internet, you just tell this kid to do it." After he finished speaking, he pointed to the head of the dynasty, as if he was not at ease, and then instructed, "Don't do any communication with those people, they provide useful information, and we will give money, so it is the fastest." ”