How to break into a math book

"He is the one who wants to marry the chief's daughter!"

The ghost stone in Tu Hua's hand was still hitting the black man's head, and he stared dumbfounded at the four black men who stopped suddenly.The leader with the gun came over, squinted his eyes and asked him, "Where did you get this ghost stone?"

Tu Hua took the dusty broken stone from the black man's face, and took a step back: "Is this stone important to you?"

The black man suddenly bowed to the sky, and said reverently: "The ghost stone is a sacred object that our tribe has lost for many years! The chief said that as long as someone can get the ghost stone, he can marry his daughter!"

Before Tu Hua's eyes, an image of a black and fat African woman appeared unconsciously, and she threw the stone on the ground like a hot potato: "Then I don't want it anymore!"

Although the black man had been emphasizing the sanctity of this ghost stone, he resisted a little, as if he was about to face some kind of scourge.He picked up the stone, stuffed it into Tu Hua's arms, and said viciously: "You take the stone and follow me back to the tribe! Otherwise, I will kill you!"

Wang Boyu scrambled and hid behind Tuhua: "Isn't it just to let you marry a wife in the game, what are you afraid of! This is a mission!"

Tu Hua glanced at him expressionlessly, stuffed the stone into Wang Boyu's arms, and said to the black man, "Actually, he is the real owner of this stone."

Wang Boyu's face turned green, and he quickly avoided: "Don't listen to his nonsense!"

The black man stared fiercely: "Who the hell?!"

Tu Hua and Wang Boyu looked at each other, pointed to Tang Bo behind the hillside and said in unison: "He!"

Tang Bo looked confused:? ?

The four of them finally worked together for a long time, and the important task of marrying the chief's daughter still fell on Tu Hua's shoulders.After all, this stone is his, and no one will take the blame for him.

Tu Hua was very frustrated. Why do other people's props are calculators, prompters, compasses, etc., but only his own is inexplicable. A Mr. X pops up in a moment, and he has to marry the chief's daughter in a moment?

Although the heart is heavy, according to the current plot trend, Tu Hua can also guess that clues about functions will inevitably appear in this tribe.He made a request to the blacks to let three of his teammates go back to the tribe with him.

The black man hesitated for a while, then nodded and said, "After all, when you marry the chief's daughter, you will be the new chief of our tribe, and we have to listen to you."

Tu Hua asked him, "Then do you want to be a chief?"

The black man nodded sincerely: "Of course I want to!"

Tu Hua stuffed the stone into the black man's arms: "Then you go and marry the chief's daughter!"

The black man returned the stone to him and said seriously, "I want to be a chief, but I don't want to marry the chief's daughter."

Tuhua: ...

On the way, Tu Hua's three teammates took turns to comfort him.Wang Boyu said: "This is just a game. Isn't it good to experience the wedding night in advance? At least accumulate some experience!"

Tang Bo: "Wang Boyu is right. It's no big deal. Maybe the chief's daughter is as beautiful as a flower?"

If it wasn't for having to go through the level with them, Tu Hua really wanted to slap these two people to death with stones.Sun Wei held back his smile and patted Tu Hua's shoulder.

Tu Hua looked at her with a mournful face, "Are you even going to mock me?"

But Sun Wei said: "I suspect that this tribe is the function we are looking for."

The ears of the remaining three were all pricked up: "How do you say it?"

"Look back at the footprints we have walked."

Tu Hua looked back and found that the route of the four black people was very strict and orderly, extending to the westernmost point, with no end in sight.Moreover, their footprints were very close to the river on the other side of the thick fog at the beginning, and then gradually shifted northward, forming an arc.

Tu Hua instantly understood what Sun Wei meant: "You mean... the route is the image of a function?"

Sun Wei nodded: "It is very possible that we can judge the function image through the route, but how to get this function... depends on you."

This main task does not give them an answer box, and it is not just for them to judge the type of function. It should also require them to obtain some kind of token from the process of the task before they can truly find this function.

Therefore, it is not a coincidence that Tu Hua got the Mingshi and was asked to marry the chief's daughter, but the key to the mission.He must get tokens related to this function from the tribe.

Soon, they encountered a thick fog in the east again.This time, the bottom of the thick fog was not a small river, but a bottomless rift valley, with a ropeway running across the middle of the rift valley.The leading black man walked into the fog and dragged the rattan cradle hanging on the cableway: "We will take this basket to the other side."

The basket hanging on the cableway does not look strong. There is a drawstring in front of the basket, which should be used for driving.Although it looks dangerous, this is the only way through this canyon.

The dense fog still covered the scene on the other side, and the cableway was as terrifying and unpredictable as if it plunged into the fog out of thin air.But the scariest thing is yet to come. The leader said: "This basket can only accommodate two people at most. It used to be driven by someone, and it needs to be driven by someone when it comes back."

"You come to formulate a method and arrange for eight people to cross the canyon safely. If..." The black man suddenly smiled sinisterly, "If we have more people than you on a certain bank, you will be killed. "

"River-crossing game!" The four exclaimed in unison.

The so-called river crossing game is a very common and classic mathematical strategy game.There are many versions, but the most well-known one is the "Three People and Three Ghosts Crossing the River Game".The original version is like this: three people and three ghosts are on the same bank to cross the river, but there is only one boat on the river, and this boat can only take two people (two ghosts or one person and one ghost), and there can be no more ghosts than people on any bank , otherwise ghosts will eat people.Players are required to set a strategy to safely send the three people and three ghosts to the opposite bank.

They have played this little game before, but now it has been changed to the "four people and four ghosts" version, so it really needs to be carefully considered.

But Tang Bo interrupted everyone with a pale face: "Don't think about it, the version of four people and four ghosts... has no solution."

"Although this is just a small strategy game, it is actually a classic model in mathematical modeling." Tang Bo explained, "I have studied mathematical modeling before, and the game of crossing the river can use modeling to find all possible answers. Three people and three ghosts have a solution, but if it is replaced by four people and four ghosts, there is no solution. (Note 1)”

Wang Boyu didn't quite understand: "No solution? What do you mean? Is there no such a safe way to send everyone to the other side?"

Tang Bo frowned and nodded.

Tu Hua confirmed to the black again: "As long as we have fewer people than you, will you kill us?"

The black man showed his white teeth excitedly: "Of course."

Tu Hua turned around and carefully sorted out the situation in this link.This should be regarded as a small level in the main task. Although the system did not jump out to promulgate the rules, it is actually the same as the side levels they have experienced before. Once they cannot complete the task, they will be eliminated.

In other words, killing in the black population is elimination.

Tu Hua carefully recalled the rules of the main level. It requires challengers to form a team to complete the task, with a limit of four people.And as long as anyone in the team clears the game, the whole team can clear it.

But it is not clear that if someone is eliminated in the middle, but someone clears the level in the end, will all the remaining players clear the level, or return to the game including the previously eliminated players to clear the level.

Tang Bo thought about it with him, and he analyzed: "All we can do now is to set up a minimum casualty plan. Some people can die in this link, as long as there are still people alive, we have a chance to pass the level."

Tu Hua thinks this plan is too risky: "If we die...the ones who are eliminated, even if we pass the level in the end, we won't be able to come back, what should we do?"

Sun Wei also disagrees: "There are loopholes in this plan itself. It is impossible to eliminate only a few people. Once black people kill us, all of us will be eliminated. As long as someone is killed by black people, our total number will be smaller than black people. Then according to the rules he gave, the small group of us left will still be killed."

Things seemed to be deadlocked.

This is an unsolvable game, but they were asked to answer it. All three of them frowned, and even wondered if they chose the wrong route at the beginning.

Only Wang Boyu looked at them strangely: "What are you thinking? Doesn't Tu Hua have a ghost stone? Isn't he going to marry the chief's daughter as the chief's son-in-law? Why would the black man kill him?"

The three looked up at the same time, looking at him in surprise.

Really, sometimes short circuits are... a good thing.

The author has something to say: Note 1: Exhaustive means to list all the situations, but there is no feasible method.

This ghost crossing the river game is very classic, if you are interested, you can search for it!

PS: I’m out for a trip, and I need a little more. If you want to add more, don’t worry, wait until I go back in two days, come and send thick and long ones!