What is exactly the finish time of one request? arrival_time + processing_time or arrival_time + processing_time + 1? As there is no clarification, you can only enumerate it. Enumerate question meaning maybe the most important ability in this contest.

The most aggressive problem is here. You are given some 2-D points and should "determine whether these points can form a convex polygon". Easy, isn't it? Just look at input format: there MAY BE some integers with some commas, but (see the last line of output format!) this input could be wrong. You should determine whether the input is in an illegal format. And what is legal or illegal input? Just guess! Guessing is the most interesting part of this contest!

However, there is NO illegal input. Some teams write almost 100 lines of code to check "illegal input" and still can't pass this problem——until they deleted all of them.

This problem seems normal. But writers may not notice answer could reach $$$10^{20}$$$, so you can pass it by just using long long.

Another tedious English reading problem. But there's something interesting: Will there always be 0.0.0.0 0 in input? Just guess!

Another aggressive problem. Good job Huawei! I said this contest you can't use clarification, but this problem indeed has a clarification (send by PTA invigilate system's dialog, once you press OK it will disappear forever). This clarification explained what neighboring points exactly are: If A and B are in the same segment or plane enclosed by a triangle, B is A's neighboring points.

I don't know whether writers understand their problem's meaning or how to write Chinese sentences, but my teammate wasted 40 minutes on geometry. Then I passed it by some stupid code. Just ignore this statement, ignore this clarification, and ignore $$$[2,n+1]$$$ lines of input. Then read the example again. That's all you need to solve this problem.

Feels like world war just finished and the whole earth is in chaos. The only thing you know is $$$|S| \leq 100000$$$. I don't know why writers are so addicted to input/output processing, but they did turn an ICPC online contest into an input formatting contest.

This is an interactive problem. You should use assert and binary search to find out the range of $$$u,v$$$.

My Computer Networking and English Reading skills are improved. Thanks, writers!