TheOpChicken123's blog

By TheOpChicken123, history, 15 months ago, In English

Hello guys, in exactly two hours I am going to be taking the NOI qualification test. It is a 5 hour OI contest to select students to take the actual NOI (singapore) which is going to be a 7.5hr exam.

Does anyone have any tips for me? Any will be greatly appreciated. Thanks.

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15 months ago, # |
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If it was an offline contest, then good luck, and be careful man. In offline contest, where you don't know whether your code will AC, people will brain fart more than you think. So, if you are feeling the problems are too hard, and you may fail, just know that the problems is hard for everyone, not just you, and there're probably dudes who completed the entire problem set then proceed to forgot to read files properly and got significantly lower score than you. But when it comes to online contest then I don't really know :D.

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    15 months ago, # ^ |
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    Thank you so much! Idk why ppl r downvoting so much. But can I ask what is the difference between online and offline contest? My contest is online btw. But the actual NOI will be offline.

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      15 months ago, # ^ |
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      Online contest are just, well, online, like on Codeforces. You can spam submission, you can know whether or not your solution are correct immediately. But in offline contest, you just sit there, with the computers (it's likely that they won't allow you to bring your own computer, for obvious reason). People hand you the problem set, you solve it, and you have to give them the code files at the end of the 3 hours. You have no way to tell whether your code are actually correct, or will it get compilation error because the judge don't have the libraries that you need. You have to stress test and try to generate strong test by yourself. You can only submit one time.

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        15 months ago, # ^ |
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        wait really? Is this true? I just assumed that an offline contest will be the same as an online contest (you are using maybe a standardised PC/laptop but using an online judge), but just at an offline venue! I will definitely stress a lot if we won't get an online judge to test our solutions!

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          15 months ago, # ^ |
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          I think there is a misunderstanding here.

          Our country's (Vietnam btw) "offline" is that you code everything, then your code will be run exactly once after the contest has ended. It might take days or even weeks for us to get the actual result.

          Your country's offline is simply the usual offline: all contestants gather at one place and solve problems there, instead of staying at home like this qualification that you are talking about.

          I don't think there are any country that still do the stupid "offline" like our country, like it just doesn't make sense and the contest doesn't always choose the best guys to advance to the next round.

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            15 months ago, # ^ |
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            Yep I think it is very weird indeed. IOI is not like this right? In IOI I believe it is basically online but everyone is at an offline venue, so it doesn't really make sense for them to not let u test ur code during the contest.

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              15 months ago, # ^ |
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              Yeah, in the IOI it's just the usual spamming submission online stuff. Like, it's just kinda BS to not let the contestants test their code. The judge flags and configs, stack size, etc... might be a lot different from the computer you are coding on. Maybe the judge doesn't have something like Policy Hash Table, or high precision random clock, maybe the "#include <bits/stdc++.h> will gives CE. I almost failed the school selection contest, because the judge use C++98 of all things (and I used auto in the for loop). It's just kinda stupid. There're people who didn't even complete a single task of the 6 tasks. They just brute-force through the hard task and scores like 80% on the easy task, and got high places, meanwhile on the other end of the spectrum there're people who theoretically get absurdly high score, but their code include something that the judge doesn't allow, thus getting 0 score. So yeah, offline contest just don't really pick the best guys, just the most consistent guys who studied the rules.

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15 months ago, # |
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how hard were the questions? im curious to see singapore's NOI

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    15 months ago, # ^ |
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    Hey,

    First question: abnormally easy. It was equivalent to finding the maximum number in an array.

    Second question: very doable

    Third question: Required a few observations, and implementation was a bit hard. But otherwise, doable.

    Fourth question: After 1 observation, it just became convex hull trick. However, due to a slight difficulty, i wasn't able to get full marks. (i posted a blog on it as well.

    Fifth question: Didn't really try cos i didn't have enough time. But I think with 2-3 hours of trying i will be able to come up with some sort of a solution.

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    15 months ago, # ^ |
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    Also note that this was only the qualification round. The actual NOI will take place in a month and will be significantly harder.