I was a top student in America.

"The diagnostic test has six major questions and takes three hours in total. Put your bag, reference books, and calculator in front of the podium."

David stood on the podium and clapped his hands. "Only pencils, erasers, water cups, and the standard draft paper are left on the table."

Everyone stood up in unison, and in no time, a row of backpacks and document bags were piled up next to the podium.

The exam papers were passed down, and the classroom immediately fell silent.

Three hours sounds like a long time, but with six questions, it's twice as many as USAMO.

Moreover, the difficulty of the summer camp questions is considerable; if you can't find the right approach immediately, you might spend one or two hours on a single question.

Ultimately, this resulted in the student not being able to finish the exam.

Li Ao didn't bother to look at anyone else. He habitually flipped the test paper over, front and back, and felt confident.

The entire paper had six questions, covering algebra, geometry, number theory, and combinatorics, with the last two being the most challenging questions.

After a moment's thought, he picked up his pen and began answering the questions.

The first question is about congruence construction in number theory.

With the help of abstract thinking, he quickly constructed a framework in his mind.

This problem doesn't actually require overly complicated construction techniques; you just need to focus on the choice of modulus and structural changes.

Skipping the steps of repeated trial and error, he wrote quickly.

Twenty minutes later, the complete proofs for the next two inequalities and the recursive sequence problem were also presented on the paper.

The first three questions were indeed not difficult; they were all variations of old IMO questions. He quickly identified them using the "learn by analogy" approach, and he hardly took any detours.

"It's just a geometric inversion, isn't that a coincidence?"

Upon seeing the fourth question, which was about plane geometry, Li Ao paused for a moment.

After scanning the problem statement, he found that it was the same type of IMO problem he had studied in the empty classroom that morning, making it easier to handle.

While pondering this in his mind, he quickly drew the auxiliary circle on the draft paper with his pencil.

When he got to the last two challenging questions, his problem-solving speed slowed down slightly.

"Suppose a sequence of positive integers satisfies a recurrence relation, and each term is divisible by the previous two terms... Prove that a sequence satisfying the condition can only fall into a finite number of equivalence classes."

After reading the question, Li Ao quickly identified two or three feasible solutions in his mind.

"Recursion plus invariants, that is the core formula of combinatorics."

He muttered something to himself, chose the safest approach, and worked his way up to complete the solution.

The only thing that surprised Li Ao was that the last question was an extremum proof using the weighted Jensen inequality.

Isn't this just walking right into the line of fire?

You should know that he had spent a lot of time working on inequalities before.

He even derived a two-sided extension proof of the weighted Hermite-Hadamard inequality.

After carefully reviewing the question, he discovered that although this challenging question was complicated, it could be solved using the bounding and scaling approach he had previously organized, which was even faster than the recursive question above.

After writing the last mathematical symbol, Li Ao stopped writing, straightened his back, and let out a long breath.

"Done."

He glanced at the clock above the blackboard and realized it was still not 3:30.

He finished answering the six major questions that normally take three hours in less than half the time.

Moreover, with the newly unlocked [Endurance] attribute, he didn't even feel tired at all.

Although he was aware of his own abilities, he couldn't help but feel somewhat satisfied at that moment.

"I'm doing alright today..."

After muttering to himself, he looked down and quickly checked the thought process, key lemmas, and final conclusions of the six questions on the test paper to make sure he hadn't missed any steps.

Looking up, I saw that everyone around me was engrossed in writing, with no time to even glance around.

Kevin, the roommate diagonally in front of me, kept scratching his head and pausing with his pen, clearly not answering the question smoothly.

As for Taylor and Ethan, one stared blankly at the draft paper, while the other repeatedly erased the previous derivations, leaving eraser shavings all over the table.

Faced with this situation, Li Ao couldn't help them and could only secretly hope that they wouldn't fall to the bottom of the rankings.

Another slight disappointment is that Benjamin and Natalia, whom Kevin specifically mentioned, were sitting quite far away, making it impossible for them to see the progress clearly.

There's still more than an hour before the exam ends, and sitting there like this is too tedious.

Since the summer camp tests aren't timed like the AMC tests and you can leave early, you might as well go to the library and read some more books.

Thinking of this, Li Ao gathered the draft paper aside and raised his hand.

"David, I'm handing in my paper."

As soon as he finished speaking, several heads popped up in unison in the classroom.

Given the sheer number and difficulty of the questions, if someone were to hand in their paper now, everyone's first reaction would be that they were planning to give up.

Even Taylor opened his mouth in surprise, while Ethan stood frozen in place, pencil in hand.

Kevin even turned his head and winked at him quickly, as if to say that even if you don't know how, you should try to write a few more steps.

David is a PhD student at UIUC, and he is currently sitting on the podium reading literature and researching his academic topic.

Hearing the noise, he looked up, frowned, and advised:

"I suggest you think about it some more. Although the initial assessment only accounts for a small part of the overall evaluation, if you give up so quickly, it will leave a bad impression on the coaches."

"Besides, it's still early."

Li Ao knew David meant well, but sitting there was just a waste of time.

In that hour or so, you could spend some time flipping through university textbooks and maybe even gain an extra 0.1 to your intelligence attribute.

So he cleared his throat: "Um... I've already finished."

If everyone's reaction to him just now was one of surprise and astonishment...

Now that these words have been spoken, many people's facial expressions have completely changed.

Looking at the paper he had only completed less than half of, his eyes were full of doubt.

Even Benjamin, who won the IMO gold medal last year, stopped writing and turned to stare at Li Ao.

He had only just finished the fourth question, and someone in the black belt group was so much faster than him?

"You finished this level of problem in just over an hour?"

"I didn't see this person last year, where did he come from?"

Quiet whispers arose in the corner of the classroom.

Hearing the commotion below, David couldn't sit still on the platform any longer and got up and walked down.

He himself was a competition student back then, and also worked as a teaching assistant at a summer camp for two years. He had seen many outstanding students who handed in their papers early, but the earliest they did was two hours after the start of the exam.

How did you finish six major questions in less than an hour and a half?

This is ridiculous.

David walked over to Li Ao's desk, snatched his answer sheet without saying a word, and quickly glanced at it.

He initially thought the whole thing was just a bunch of simplistic, illegible steps, but as he read on, he fell silent.

The solutions to the first few questions were flawless.

The conclusion is correct, the key lemma is not omitted, and even the boundary cases are clearly written.

David hadn't turned the page yet, but his fingers tightened around the paper.

He looked Li Ao up and down again, paused for a few seconds, and then spoke:

"Okay, I'll take the test paper. You can leave now."

After saying that, he took the test paper and walked quickly back to the podium, grabbed a red pen, and began to grade it directly without being able to contain his curiosity.

……