It was a dark room sealed with steel. A huge blue clock exuded a faint glow and became the light source. Once the truth clock finished saying this, Fu Wenduo asked the same question as the previous round and unraveled the players suppression in the world of truth. Once they gained freedom, Tang Mo stepped towards the truth clock and stood under this big clock.

The next moment, Tang Mo reached out and moved through the blue clock.

His hand touched something steady and Tang Mo closed his eyes, sighing softly. His lips curved and he opened the door.

The clear sound of the door opening filled the room. Zhao Xiaofei and Li Miaomiao stood in the same position with a shocked expression. They might be able to move freely but they could only stare at Tang Mos back. They hadnt yet recovered from the great changes that just happened.

What did he mean by the second round was already over?

They hadnt started playing the hide-and-seek game yet. They hadnt entered any corridors and left any footprints. How could the second round be over?

However, the truth clock didnt lie. They definitely couldnt win this round of the game.

Zhao Xiaofei and Li Miaomiaos lips tightened as they racked their brains to understand what was going on.

Tang Mo said, Sure enough, this is just across from the staircase.

The group recovered their souls and rushed over. No one expected that there was an extremely hidden door behind the truth clock. After opening the door, Li Miaomiao looked at the scene outside and was startled. This is another staircase? Li Miaomiao seemed to think of something and she ran to the other side of the room to the door they had entered.

The two doors corresponded to each other.

Go down the staircase and they could directly enter the room of the truth clock. If they didnt look back and kept walking through this room to the other staircase then they would reach the second staircase and go upstairs to the second floor.

The room of the truth clock became an intermediate pa.s.sage connecting the two staircases.

Zhao Xiaofei felt that she had grasped the key. If we want to clear the game of hide-and-seek, we must find this door? It should be like this judging from Tang Mos reaction. However, she still didnt understand. Why have we lost? We havent started the second round of the game yet.

Tang Mo explained, It is because when we stand in this room, it means we can no longer find all the rooms.

Zhao Xiaofei was stunned.

The two doors were both opened and the two staircases were visible to the players. Schrodinger was no longer speaking but everyone knew that the black cat must be using his green eyes to stare at every player in the room and the blue clock.

Everything was actually very simple.

In the last round of the game, I asked Li Miaomiao to ask the truth clock a question.

Li Miaomiao recalled it. I asked how we can clear this game of hide-and-seek.

Tang Mo nodded. Yes, this is your question. Then when the truth clock answered, the black tower masked the answer for the fairness of the game. We didnt hear any answers. The black tower told us that the truth clock was correct and wasnt lying. The question ended.

Everyone remembered this incident. At the time, they were so angry that they wanted to throw Schrodingers cat food at the black tower.

Li Miaomiao asked, So what?

The answer was blocked by the black tower. What was the point of the question?

Tang Mo smiled. The black tower blocked the answer but it didnt block the words before the answer.

Everyone thought about what the truth clock said at the time. Then a steady male voice was heard. It said there was only one way to clear the game.

A moment later, Tang Mo looked up at Fu Wenduo and replied, Yes, it said there was only one way to find Schrodinger.

Li Miaomiao was still a bit stunned. Then what is the only method?

The black tower already told us this method.

Li Miaomiao and Zhao Xiaofei spoke in unison, The seventh rule of the game, look in all the rooms and we can find Schrodinger?

Yes. Tang Mo stated. Schrodinger can lie and the truth clock can lie. However, the black tower never lies. It only conceals the conditions, buries traps, reduces the amount of information and even misleads players. Still, it will never lie. Thus, there is only one way to clear the game. Look in all the rooms and we will find Schrodinger. Then the problem is simple. It is a one stroke problem. The problem is just a bit complicated because castle cant be finished in one stroke.

Four hours ago, Tang Mo listened to the black tower explain the rules of the game and determined that each corridor could only be entered once. At the time, he remembered a graphic problem he once encountered on the civil servant examination for university graduates.

He needed to pa.s.s the exam to become a librarian in Suzhou. The graphic problem looked extremely complex and the four options were staggered. The requirement was to select which of the four figures couldnt be completed in one stroke. Tang Mo spend five minutes to choose the correct answer. At the time, he was vaguely away that there must be some type of theorem behind the stroke problems.

Tang Mo suddenly thought that if Chen Shanshan had partic.i.p.ated in this tower attack game, the game wouldve ended a long time ago.

At the start of the tower attack game, Tang Mo didnt know the theorem. Then he walked out of the kitchen, looked for Schrodinger and understood the map of the steel fortress. Tang Mo drew a variety of patterns in his heart as he looked for the theorem. The five people walked through the second floor and Tang Mo discovered what this theorem was and demonstrated it. Then a problem suddenly emerged.

This fortress could never be finished with one stroke.

It was because it had two stairs.

Any closed graphic that needs to be finished with one stroke requires a precondition. At the intersections, there can only be 0 or 2 odd intersections. As long as the graphic doesnt meet this condition, it is impossible to finish it in one stroke.

Odd intersections referred to an intersection which had an odd number of lines. Take Schrodingers steel fortress for example. Tang Mo found the second door hidden in the truth clock room, making it an odd intersection. From this point, there were three paths they could go. Go up the stairs, go the hallway to the left or go to the hallway to the right.

The players thinking speed had improved after the earth went online. Zhao Xiaofei and Li Miaomiao didnt know the theorem but they thought about it several times and figured it out.

Zhao Xiaofei said, If this is the case, there are two stairs in this castle. Each staircase has an odd point on both sides. Altogether, there are four odd points. It is impossible to walk through all the corridors without going back!

If there are two odd points then it could be turned into an even point. Tang Mo looked at Fu Wenduo.

10 minutes ago, they walked at the bottom of the second staircase and Fu Wenduo whispered in Tang Mos ears. He said that in this position, the room of the truth clock would be to their left.

The conditions to find this hidden door were extremely demanding.

First of all, the players had to know that there was only one way to find Schrodinger and it was to find all the rooms. Finding all the rooms meant the player had to complete a single stroke game.

Secondly, they had to figure out the basic map of the two floors in the first round of the game. They had to know the theorem of the stroke problem and find the truth in the second round of the game. They had to find this hidden door and turn this steel fortress into a viable place that could be completed in one stroke.

Finally, they needed a player like Fu Wenduo with strong spatial thinking and memory.

Tang Mo had been thinking about how to turn four odd points into two. He didnt discover that the two corridors corresponded to each other and that the truth clock room was in the middle.

All the above conditions were indispensable. If the players won the game in the truth clock room and left after winning, they wouldnt be able to find the truth.

Tang Mo explained, The odd points have to be either 0 or 2. This is the first condition to complete the one stroke problem. The second condition is that our starting point must be an odd point. We cant walk casually in the second round because in the third round, we have to start from a certain fixed point. If we dont start walking from an odd point then we cant find Schrodinger, even if we know the truth.

Tang Mo chose to enter the truth clock room to determine the true odd point.

The room of the truth clock was located on an odd point. However, it wasnt really an odd point. Thus, they could no longer win even if they hadnt started the second round. This was the truth that Tang Mo wanted to know from the truth clock.

Grecia smiled. This is Schrodingers fortress and he can certainly move freely through every room. If we dont look through all the rooms, he can hide in a room that the players havent entered. It is only when we search all the rooms that he doesnt dare to cheat. This game is really interesting, Great Schrodinger.

You shameless humans! The small black cat shouted. However, no one gave it face.

They knew the method to clear the game and also found the hidden door. The five players left the room, ready for the next round of the game.

Before leaving the room, Tang Mo glanced at the truth clock.

The second hand moved on the blue clock. This clock was like an ordinary clock. It said from the beginning that it accurately told time for Schrodinger. Schrodinger only needed it to accurately report the time.

It wasnt a coincidence that the truth clock was arranged in this special room.

Tang Mo smiled and shook his head before walking out of the room.

The black tower closed one eye and allowed Schrodinger to cheat by letting him move freely through the 108 rooms. The black tower also gave players a hint. The truth clock was the hint. If the truth clock wasnt placed here then the difficulty of the game would increase dramatically. Tang Mo wouldnt know the real method to clear the game and Fu Wenduo wouldnt get the impression that the left and right stairs corresponded to each other.

The five players walked to the beginning of the corridor. Li Miaomiao wanted to walk more but Tang Mo stopped her.

Tang Mo raised his head and asked, Black tower, can we just give up the second round and start the third round of hide-and seek?

The black cat shouted, You b.a.s.t.a.r.d!

The black tower replied in an emotionless voice. Yes. Please confirm that you will give up on the second round.

Tang Mo declared, We give up.

Ding dong! The second round of hide-and-seek game has ended and the players have failed. After a 10 minute break, the third round of the hide-and-seek game is open.

The author has something to say:

Tang Tang: It is really safe to be with Old Fu.

Old Fu: I really want to ask the truth clock a question

TL: This theorem that Tang Mo explained is based on an Eulerian trail. Link below. It is mathematics so I gave up on understanding it. Some of you will probably have better luck =). I see one commenter who got it in an earlier chapter.

https://en.wikipedia.org/wiki/Eulerian_path

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