drowning

Xu Yanxin ten years ago was not much different from now. His smiling diamond-shaped lips and sweet dimples all showed his good temper, but he seldom smiled at that time.Just like an unwritten rule, a student like him shouldn't show such a bright smile, it could easily be taken as complacency.So most of the time, he had a bitter face.

It's like standing in front of the math grade director at this moment.

The grade director's surname is Wang, and his name is Qingshi. He is a vigorous old man. No. 12 Middle School recruited a mathematics expert from another school with a high salary.Wang Qingshi has always been peaceful, and facing his unreasonable request, he only drank a sip of Longjing tea before Shi Shiran said: "You can't quit the math class just because of a small failure. You are in the second year of high school, you quit the competition class and transfer to the science class." Class is like preparing for a competition for so long, but you have to rely on the college entrance examination to enter the university. You are not worth the loss."

Xu Yanxin said: "Teacher, I don't think I am suitable for competition."

Wang Qingshi smiled briefly, and said: "If you are not suitable, then no one in No. [-] Middle School is suitable. I know that the school motto of No. [-] Middle School is 'free and knowledgeable', and you have the right to make class adjustments beyond your parents and teachers. Right, but how long it takes to pass is the teacher's right." Xu Yanxin took a breath and said, "Teacher, you won't wait until the college entrance examination is over before passing my application for class transfer?"

"Look at this question, last year's Russia Global Cup Autumn Competition." Wang Qingshi pursed his lips and smiled, "If you can solve it within 5 minutes, I will let you transfer from math class to science class, otherwise you will be obediently." Stay in the competition class and lead the team."

Xu Yanxin said hesitantly: "Teacher, you won't wait for me to solve it, tell me that I'm just a seedling of mathematics and won't let me go?" Wang Qingshi laughed and said: "It's possible, then you try it or not?" ?" Xu Yanxin said inwardly, I have no other choice, so I had to wrinkle my face, take out a fountain pen from the pen holder, and pick up the draft paper to do calculations.

The topic is as follows: One hundred pirates play cards and gamble for money. When the game is over, they use gold sand to repay the gambling debt. Each pirate has enough gold sand to pay the gambling debt.Pirates are only allowed to pay and receive gold dust in the following ways: (a) pay equal amounts of gold dust to all other pirates; (b) collect equal amounts of gold dust from all other pirates.

Please prove that after receiving and paying in the above-mentioned way for a finite number of times, every pirate who wins can receive exactly what he should pay, and every pirate who loses can pay exactly what he should pay.

This question is not difficult, it belongs to the simple ones in the competition.But to solve it in 5 minutes, you have to use some ingenuity.

Assuming that the kth pirate wants to pay Ak, each pirate needs to pay others, and A1+A2+A3...+A99+A100=0, the next step is the pure mathematical operation of the formula, Wang Qingshi did not let him Continue to count, but raised his chin towards him, he looked at the clock in the office, only 2 minutes had passed.

But Wang Qingshi said to him with ease: "Does your mother know about your transfer?"

Xu Yanxin's hand holding the pen tightened, but she didn't show it on her face: "I know."

Wang Qingshi's expression was gloomy, and he said: "If you think it through clearly, go to the dean to make a list."

He finally breathed a sigh of relief.

But Wang Qingshi said behind his back: "Yanxin, Ruqing is right, you do have a talent for mathematics. I will wait for you to come back." Xu Yanxin stuck out her tongue at him and joked: "Coach, I want to learn basketball." Wang Qingshi almost sprayed tea, mumbling, not serious.He closed the office door, and the heat from the summer heat hit his face, making his skin sticky.He looked down at his fingers, the middle finger was rubbed with a pen mark.When he picked up the pen, he couldn't help but think back to the scene in this year's selection competition.

My whole body is cold and my mind is blank.

He took a deep breath. There were very few people in the corridor of the No. [-] Middle School. The rare students he saw all went to the office. He was about to go to the Academic Affairs Office to make a list and move his schoolbag to the science class, but he was rushed by the people behind. It was a classmate in the mathematics class who was yelling non-stop, shouting: "God Xu, are you not staying in the math class? Then the math class will become Ye Yuqing's women's army. Ahhhh, how could it be like this. "

Xu Yanxin smiled and said, "I retired behind the scenes and retired to the mountains and forests. You all work hard to prove Goldbach's conjecture as soon as possible."

The classmate looked at him disapprovingly, and said, "Then you are really going to go to the science class? Are you not going to participate in the competition? This, this is such a pity! This is like Hua Luogeng going to study art!"

"I learned how to play basketball," he raised his hand, "lead the No. [-] middle school to enter the country."

"Okay. The basketball team in the No. [-] Middle School is completely hopeless," the classmate suddenly remembered, "Speaking of the basketball team, you must not get involved with the one in the science class. Be careful that your head will be bloody and your life will be on the line." line."

Xu Yanxin didn't care much: "Is even basketball so dangerous now? I thought only the tennis world needed to save my life."

Seeing that he didn't take it seriously, the classmate emphasized again and again: "Don't get involved with him." Xu Yanxin said yes, and packed her luggage to go to the science class.When he stepped into the math class, the whole class sighed as if the fire was turned off. Ye Yuqing, who was sitting next to him, had sharp eyes as if he was her father-killing enemy, and Xu Yanxin was quiet in front of everyone. The geography textbooks were all bad. Mathematical competition test questions.He was holding the book, and just as he was about to leave the math class, he heard Ye Yuqing pick up the fallen sketchbook and stop him. Just as he was about to say thank you, he heard Ye Yuqing frowned and said, "That's why you left the math class?"

Xu Yanxin didn't speak, and took the notebook in her hand with a smile.But Ye Yuqing was angry because of this: "It's ridiculous." He turned and left without denying it, the sun was hot outside, the leaves were green and dripping water, and he casually stuffed the sketchbook into a few test questions.

As the No. [-] Middle School, one of the best in S City, its science classes have a few weird ones.

Fang Keshi, male, his dream is to marry Asuka as his wife, so his goal is to become a first-class artificial intelligence expert, create his wife from the animation world, and become the "cornerstone" of science classes.He wears a pair of [-]-degree glasses, but he is not gloomy, on the contrary, he is overly active.As soon as the get out of class bell rang, he rushed to the last row of seats and woke up the boy who had slept for three classes. The boy's hair was curled up in sleep, and his handsome face was covered with red marks.Fang Keshi said sadly: "Jiang Yu, you are a handsome guy, can you wipe your eye poo?" Jiang Yu yawned nonchalantly, brushed off the dirty things that affected his appearance, and let everyone in the class Girls look comfortable.

"Let it go if you fart."

"The latest news, TOP1 in the math class will be transferred to our class."

Jiang Yu propped up his arms and stroked his hair: "Is he tall?"

Fang Keshi was so anxious that he wanted to hit him, but due to the disparity in strength, he had no choice but to give him a light iron fist on his chest: "The total score of CMO is the first in the city, the love of all the teachers, the girl's Bai Yueguang, Xu Yanxin Ah, I heard that he didn't perform well in the trials this time, he didn't make it to the national team, he gave up on himself and didn't plan to recruit himself into the P University, and wanted to take the test naked."

"Oh." Jiang Yu picked his ears.

Fang Keshi added: "The total score is 600, and he scored 583 in the simulation paper last year."

Jiang Yu blew his nose and said, "It's awesome."

Fang Keshi covered his chest, and said: "All the 'children from other people's families' of high school students in our city spend most of their time preparing for competitions outside the school, and I haven't seen him a few times, and then I have to go to class with him every day , I can also see him handing you homework and asking why you didn’t hand in your homework. It is even rumored among the juniors that if you shake hands with him, you can pass the P University and go to the pinnacle of your life. You actually said that he is just "good" ?!"

Jiang Yu sneered and said, "That's awesome, when he comes, hurry up and give him a hug."

Fang Keshi said: "Don't say that, although he is very good, but I want to be a double hero with you, will you go or not at noon today?" He laughed meanly, and pointed to the wall and fence.

Jiang Yu replied blankly: "Dog, you are the most dog."

As soon as the class bell rang, Fang Ke rubbed the soles of his feet with oil and quickly sat back in the first row. Just as he was about to lie down and sleep, someone poked his shoulder. He frowned and raised his head, seeing He had a white face, his shirt was buttoned to the top, his blue and black plaid tie was neatly tied, and even his sneakers were spotless white.

"Student, is there anyone here?"

Jiang Yu glanced at the seat next door occupied by his schoolbag, raised his eyelids and looked at him: "Do you want to sit here?"

The visitor said politely: "If you find it troublesome, forget it."

Jiang Yu lowered his head and said, "Trouble."

The boy nodded in a good-tempered manner, and walked forward. He found a place to live amidst the whispers among the students.It was Fang Keshi who had just worked hard to promote him.The young man had a good sitting posture, his back was straight, and his body smelled like ink.Only Jiang Yu noticed that his sleeve was stained with unclean gouache.