Hi everyone, I'm a grade 10 student from Hong Kong and recently, I have prepared a programming contest for some secondary school students (grade 7 — 12). They are mostly (70%) beginners (Learnt OI for a month only) and some of them knows some intermediate concepts / algorithms (like greedy, binary search, partial sum etc, actually not really intermediate stuff).
I'm also the first time making a contest and therefore I want to ask for opinions / suggestions towards the problems. Like how are they done? Would they be too easy / hard? Is the problem statement clear enough? Are the subtasks score distribution appropirate? Are the examples provided appropirate? How can the problems be improved?
Btw this contest will be run on Codeforces and in IOI-style, are there any things that need to be careful with?
Hope someone can give me some opinions towards my contest, thanks for y'alls help!
Auto comment: topic has been updated by jonahgamer110 (previous revision, new revision, compare).
Auto comment: topic has been updated by jonahgamer110 (previous revision, new revision, compare).
I feel like subtasks for B and C are unnecessary.
Yea I'm planning to cancel them too. But maybe some students were really weak (don't even know how to write modulo) and i decided to give some mercy to them lol :)
Problem B should've had multiple test cases, otherwise I can just output one of the three outcomes.
Yeah the contest will be in IOI-style, there will be multiple test cases for each subtask.
For problem D I feel like it should be output the answer modulo 1e9+7 or somthing like that instead of handling with 128bit ints
I also think so. Handling 128bit ints somtimes cause unrelated errors.
Yeah you’re absolutely right! My concern is that many beginners don’t know what is modulo arithmetic and some properties (like (a + b) mod n = (a mod n + b mod n) mod n). So I decided to use int128. But yeah, you’re right cuz int128 may cause unexpected errors. I’m planning to replace it to another problem in the future.
Maybe you could add some explanation about it, so they can learn it
I might be wrong, but if the length, width, and height are not the same, then it’s actually a cuboid rather than a cube. So, the problem statement could be more precise as: “A cuboid has a width of W units, length of L units, and height of H units. Find its surface area.” Since a cube is just a special case of a cuboid where length = width = height, this phrasing would make the statement more accurate.
Thanks for your correction!
At the bottom of catalog, there is a topic "problemsetting", i think u can read a lot of interesting and useful there
Unless I'm missing something, shouldn't the answer for 2 be 4? ( 1 * 2 + 2 * 1 ) on problem D?
Overall really like the problem set.
A couple of suggestions:
I know that A is a basic problem that barely requires memory usage, but 4 megabytes feels too low to me.
While probably not relevant if you plan to not allow googling, but D is OEISable https://oeis.org/A052149 and is also on Project Euler, though the Project Euler version is easier.
If you're going for ordering by difficulty, move D further into the problemset.
Minor typo in G, but it should be nothing can be sold on that day.
Thanks for your suggestion! I’ll fix problem D examples soon. You said move D further into the problemset, so what you meant is move it to like problem E or F? Btw, actually I think I’ll remove problem D as it’s quite weird actually, replace it with another problem.
You said move D further into the problemset, so what you meant is move it to like problem E or F?Yeah, probably F.
Btw, actually I think I’ll remove problem D as it’s quite weird actually, replace it with another problem.While I do think it's a nice problem, I do agree, since I'm not sure that people new to olympiad have the sum of squares formula memorized (I personally had to google it to make sure I was remembering it right).