KALARRY's blog

By KALARRY, history, 13 months ago, In English

Hello everyone, I participated in BOI 2023 and I am very disappointed about the competition. In day one's first problem(Car Race) some N*log(N)*log(N) solutions with small memory optimizations passed for 100%, while others got only 58% despite the fact that N could reach 10^6. The second task of day 1(Weights) had a subtask for O(Q*depth) with depth smaller than 30 that was supposed to get someone 24 points (for the other subtasks a faster solution was needed and someone had to adjust the way he stored numbers as they could reach values up to 2^depth which could turn out to be really large). However, naive solutions for ONLY the third subtask with __int128 could earn 91 points. Moreover, many solutions for the problem passed the last subtask(the no further constraints one) but they lost points from the first one. How is this even possible? Last but not least, in the last task of day 2 (Aliens), O(N^2) solutions that required N^2 memory passed K=1 and N <= 10^5. How were all these problems not prevented from the Scientific Committee and from those who tested the problems? Were the testcases never checked and solutions for subtask never tested? All these problems are the ones that make students refrain from participating in Olympiads and I hope that Problem Seters will be more careful in the future.

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