The Stunned Liu Bin

As a Grind King-level student who maintained a daily study regimen of 14.4 hours, Xiao Yi had cultivated the habit of thinking through problems in his mind even while eating or walking.

Of course, for him, this method of studying in his head was just a way to keep his buff going; it wasn't as rewarding as directly reading books or solving practical problems.

After all, the ultimate goal of his studying was to gain more knowledge—keeping the buff up was purely a side benefit.

So, when he spotted a math problem written on a small blackboard halfway down the road, it naturally drew him in like a magnet.

It was like stumbling upon a wild experience pack on the road—who wouldn't pick it up?

And besides...

This wild experience pack was pretty high-quality.

"Hmm... the problems from the past two days were pretty challenging—the hardest I've encountered in all my studying so far."

As he walked toward the blackboard, Xiao Yi thought to himself.

Before this, he had been working on the papers the teacher handed out, exercise books, and reference materials like the Wu San he'd bought himself. But none of those problems could stump him, and they'd even started to bore him.

Then, the day before yesterday, after finishing his afternoon meal, he passed by here, glanced over, and saw this math problem. To his surprise, it was a type he'd never done before—quite difficult!

It took him a full three minutes to figure out the solution!

That got him excited. It was way more interesting than the problems in his exercise books, which he could solve in under half a minute at most.

"Especially yesterday's problem—it was a bit harder than the day before's. Took me almost five minutes to crack it. I wonder if today's will be even tougher."

Thinking this, Xiao Yi already felt a sense of impatience bubbling up inside him.

He quickened his pace, hurried over to the small blackboard, and looked at the problem written on it.

[Find all positive integers n such that there exists P(x)∈Z[x] satisfying: for any positive integer m, p^(m)(1), p^(m)(2), ..., p^(m)(n) have exactly n/2^m distinct remainders modulo n, where p^(m) denotes the m-th iteration of p.]

Seeing this problem, Xiao Yi raised an eyebrow.

"Oh... this problem seems..."

Extremely interesting?

First, in terms of difficulty, Xiao Yi could be sure it was several levels harder than the problems from the past two days.

In terms of type, this problem was also completely different—again, something he'd never done before.

Even the information given in the problem statement was pretty niche in math books, the kind that rarely appeared.

For example, the ceiling function symbol "⌈x⌉" and the concept of iteration.

At least... as a sophomore in high school, he hadn't learned these things in class.

Thinking that this was the senior year building, he couldn't help but sigh in admiration: "So this is the level of problems the senior students have to face."

Truly worthy of the mighty seniors!

Facing the college entrance exam, they got to tackle such challenging problems.

For a moment, he even looked forward to his own senior year—how wonderful would it be to do problems like this every day!

Xiao Yi: (▽).

After a brief moment of joy, he quickly set those thoughts aside and focused seriously on the problem.

Although these concepts had never been taught in class, they had all appeared in the dozen or so math books he'd already read.

So he could fully understand the problem's meaning.

Then, he began to think seriously about how to solve it.

A storm of ideas quietly unfolded in his mind, and the effect of the [Ruthless Continuous Study] at the tenth level began to take effect.

But of course, no one else could see this "storm."

Meanwhile, on the other side of the hallway.

"Is that the student?"

Liu Bin squinted, his eyes fixed tightly on the student standing before the blackboard, the light reflecting off his glasses.

Beside him, Chen Liang also watched the student, racking his brain to recall if any math prodigy in the entire senior year matched this student's description.

But unfortunately, nothing came to mind.

"No idea. Let's watch for now. Looks like he's a sophomore."

Liu Bin started walking over. "Come on, let's go take a look directly."

Chen Liang grabbed Liu Bin's arm. "Let's wait and see first. If it's not him, the real student might not come over if they see us standing there."

Liu Bin thought for a moment, then nodded. "Fair point."

He returned to his original spot, one hand on his hip and the other pinching his chin. "If it really is him, I'm curious how long it'll take him to solve this problem."

Chen Liang said, "Didn't you say this problem is harder than the last two days' problems combined? Maybe it'll stump him."

Liu Bin smiled. "That's possible too."

"This problem is a tough one I carefully picked. You know about the IMO Preliminary Problem, right?"

Chen Liang nodded and said, "I know. Every year, the problem-setting groups for each country's Math Olympiad send some problems to the International Mathematical Olympiad committee, and then the committee selects a few as preliminary problems for the next year's participating students to train with."

"Yes." Liu Bin nodded. "And this problem is the hardest among this year's IMO Preliminary Problems. In fact, it ranks among the toughest in IMO history—far more difficult than many problems chosen as official IMO questions."

"To put it simply, this problem was too hard, so it wasn't selected as an official problem."

Chen Liang's eyes widened. "That ridiculous?"

"That's how ridiculous it is." Liu Bin nodded, then raised an eyebrow. "So, this student might not even be able to solve it. Even if they can, I estimate it'll take at least half an hour... an hour isn't out of the question."

Chen Liang nodded.

But just then, something even more absurd happened. They saw the student standing in front of the small blackboard pick up the chalk placed nearby and start writing on it.

The opening character—"Solution"—immediately made them recognize that this student was definitely the mysterious student from two days ago!

Liu Bin didn't hesitate. He walked straight over, and Chen Liang quickly followed.

Behind them, other senior-year teachers also trailed along.

After all, who wasn't curious about this mysterious student?

And so, their group marched over in a crowd.

However, since where they stood was still a distance from that small blackboard—roughly the length of an entire corridor—it would take a while to get there.

They walked over, watching the student smoothly write out the solution steps line by line.

There wasn't even a single pause in the process.

Finally, they reached the blackboard.

And at that moment, the student had already finished writing the solution, putting down the period that marked the end.

Liu Bin stared at the solution, his gaze frozen.

New book, please collect and recommend!