Although the three of them still can't say what the intrinsic connection between the setting of the Rubik's Cube and the final solution will be, at least one thing is clearly visible, that is, the rotation of these rooms can be determined. That is, each rotation is a joint rotation of nine rooms in the same plane, and if you know this, at least they will not have a situation where they don't even know where they are going.

Cheng Ruxue said: "I think we have two issues to consider now, one is which room the exit is in now, and the other is which room we are in now. ”

Zheng Xiaofeng nodded in agreement, and said, "It should be easier to guess where we are, but it's hard to say where the exit is, after all, we don't know if there are other turns in places we can't see." ”

Cheng Ruxue said: "The best situation is that there is only one exit here, in that case, that is, no matter how many times the entire Rubik's Cube rotates, the exit is fixed there, if not, the situation will be much more troublesome, and then we even need to guess where the exit is more likely to be, and use probability to solve the problem." ”

Of course, no matter what the possibility is, it's a story for now, and the solution has to be done step by step.

"We might as well start from the beginning and revisit the route of each movement since we came in." Zheng Xiaofeng proposed.

The three of them began to think together, when they first entered, they saw that there was a gap in front of them, on the ground, and in the wall on the left, and the gap behind them was the exit, not counting, that is, their initial position was in a room in the corner of the Rubik's Cube.

Dong Que said: "When we wanted to leave, we heard this girl's cry for help, so we turned around and walked straight ahead for two rooms in a row. ”

At this time, they walked to the other corner of the Rubik's Cube.

"Next, when we walked back, we found that the second room had been transferred, but at this time we were actually still on the top ......floor of the Rubik's Cube," Zheng Xiaofeng continued, but at this point, the three of them suddenly realized a problem that made people laugh and cry, "Wait...... It seems like...... If there had only been one rotation in the room at that time, the exit would still be in close proximity to us! However, we hesitated for too long because we noticed the sudden change in the room, and before we could walk back, we were transferred to the bottom floor! ”

Dong Que had to squirt blood on the spot and scolded: "Smash the grass!" If we had gone back firmly, there would have been no such?! No, it doesn't have to be that time, even if we choose to run that way after the rotation starts, it's not like there's no chance! ”

Zheng Xiaofeng shook his head bitterly and said, "I'm afraid that's really the case." ”

The two of them couldn't help but scold the street, this is really too grassy, if there was no choice at the beginning, it would have been a choice, but they chose wrongly, and as a result, they came to such a fucking situation, and anyone in their hearts was 10,000 grass and mud horses galloping together. Cheng Ruxue comforted: "We can make such a choice, probably in West German Landsted, it seems that this person is more powerful than we imagined, not only mathematics, casting, carving and even psychology He is probably very proficient, at that time, in the face of that situation, anyone should make the same choice as us, with those spikes pressing, the first reaction of normal people will be to run closer behind, and it is inevitable to miss the exit." ”

Cheng Ruxue's words actually make sense, but it is still difficult for the three of them to be relieved, after all, this is equivalent to them being played hard by West Landsted, and this is still an ancient person who died thousands of years ago.

It took a while for the three of them to get out of the mood of "grief". After a long time, Zheng Xiaofeng said: "I have an immature idea now. ”

Cheng Ruxue and Dong Que looked at him, meaning: "You say."

Zheng Xiaofeng said: "We can imagine that this Rubik's Cube is the same as the Rubik's Cube we usually see, at the beginning, the six sides have six different colors. Let's say that when we first come in, the six faces are in the very first position, i.e., each side is the same color, and after we do it, the colors are all disrupted. Is it possible that when we rotate the entire Rubik's Cube back to its original position, that is, in our imagination, the color of the six faces is the same again, the mechanism will stop rotating completely? ”

Cheng Ruxue thought for a moment and said, "I don't rule out this possibility, but will it be too difficult?" After all, this 'color' only exists in our imagination, and we are inside the Rubik's Cube, and the thinking angle must be limited, not to mention that the Rubik's Cube should have been invented in modern times, not to mention the Rubik's Cube reduction formula. ”

Zheng Xiaofeng was silent for a while, this was the only idea he could find from the perspective of the Rubik's Cube.

But at this time, Dong Que said: "I think you seem to be thinking about things complicated again, and you shouldn't need a complicated reduction formula to restore this Rubik's Cube, you should just have a hand." ”

Both of them were puzzled for a while, and Cheng Ruxue asked suspiciously, "Why do you say that?" ”

Dong Que said: "Do you think, we have only experienced a few rotations just now, when we usually play the Rubik's Cube, if we only rotate the Rubik's Cube a few times, and then remember the order and direction of these rotations, as long as we do it the other way around, isn't it possible for everyone to restore the six sides back?" ”

Cheng Ruxue let out an "oh" at this time, and suddenly realized, it seems that she always likes to subconsciously think about problems, and the habit of being smart and being mistaken by smart should really pay more attention to it in the future and change it well.

"Anyway, anyway, we still have to return to the first two questions, let's continue to review first, and then talk about other things when it's over." Zheng Xiaofeng finally concluded.

Cheng Ruxue said: "In order to facilitate the review, we might as well establish a Cartesian coordinate system first, and use coordinates to represent 27 positions, so as to avoid the trouble of describing in language, and it is easier to mess up." ”

Zheng Xiaofeng said: "Good idea, I agree." ”

However, Dong Que looked a little confused, and said: "Cartesian coordinate system, I probably know what it is, but the specific ......"

Zheng Xiaofeng said: "It's okay, let's say, you just listen." ”

"Then let's make a rule, set the coordinates of the room where you first came in to (1,1,1), the room where you found the girl is (3,1,1), and the farthest from the initial room is (3,3,3)." Cheng Ruxue began to talk about it, probably influenced by the atmosphere here, and they are always willing to speak some mathematical language when communicating, "We experienced the first rotation in room (2,1,1), one hundred and eighty degrees, and then we arrived at the position of (2,3,3), escaped death, and came to the room with many geometric objects, and the coordinates should be (3,3,3)." ”

Zheng Xiaofeng took over the conversation, and continued: "Then we arrived at the first room full of stone slabs, the position is (3,2,3), and the next few rotations are all the so-called 'Z-axis coordinates', and we are still in the position of (3,2,3). ”

In this way, the first problem is solved, and the next question is what will be the coordinates of the exit at this moment.

As Cheng Ruxue said, if the exit position is the simplest situation, then the next thing they have to think about is how to change themselves from (3,2,3) back to (1,1,1).

At this time, Zheng Xiaofeng's eyes suddenly lit up and said, "I remember, the location of the exit should really not change." ”

Dong Que was taken aback, so he hurriedly said, "Teacher Zheng, please speak." ”

Zheng Xiaofeng explained: "You think, we slid down the tunnel, and at that time we could clearly see that the wall of the first room was connected to the soil, that is, its movement would be blocked by the soil, so the exit could only be in that position from beginning to end. As for the other rooms, it's hard to say, West Translands probably has hollowed out the soil near them, or maybe we're in a huge pit of natural formation. ”

Dong Que listened to it and nodded again and again: "This must be the case." ”

Cheng Ruxue's thinking was one step faster than Zheng Xiaofeng's, and said: "In that case, there are at least three directions in the entire Rubik's Cube that can never be rotated, because the first room is fixed, then the three sides where it is located, and the nine rooms on each side will be locked there forever with it, even if it wants to move, it can only be the rotation of other faces, and these three sides will definitely not work." Maybe this point can also be used by us, and when we find a way later, we may be able to eliminate many possibilities and reduce some detours. ”

As soon as the words fell, the girl suddenly coughed violently, and the thoughts of the three people were pulled back at once, and they hurriedly went to check her injuries. Her cough was so severe that people thought she was dying, but upon closer inspection, she found that many of the wounds on her body had actually condensed, and the cough seemed to be just a physiological reaction caused by excessive pain.

Cheng Ruxue touched her pulse and said in surprise: "The heartbeat seems to be stronger than before!" ”

Dong Que hurriedly made a series of complicated gestures, put his hand on the girl's forehead, and said happily: "It seems that this is really useful!" ”