Is ICPC ECNA 2023 problem C straight-up wrong?

Revision en1, by Zhtluo, 2024-01-04 08:44:35

So I was studying this infamous ICPC ECNA 2023 geo problem (https://codeforces.net/gym/104757/problem/C)...

I tried to read the judge's solutions here (https://raw.githubusercontent.com/icpc/na-ecna-archive/main/2023-2024/convexhullextension.zip) from this site (https://na.icpc.global/2022-23/regionals/ecna/ecna-archive-2022-23/) but they don't really make sense to me.

So I came up with this test case:

5
-999 999
-998 -998
999 -999
998 999
0 1000

And I tried to run it on the solutions. It turns out that the solutions don't agree with each other...

So now I am stumped. What is the correct solution for this problem? Does it even exist?

Tags acm-icpc, ecna, geometry

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  Rev. Lang. By When Δ Comment
en2 English Zhtluo 2024-01-04 08:45:52 47
en1 English Zhtluo 2024-01-04 08:44:35 915 Initial revision (published)