ez_zh's blog

By ez_zh, history, 6 years ago, In English

Problem link: AGC005D

You can use DP to solve this problem in O(NK).

This code got AC when N<=2000 and K<=N-1.

DP Solution (29ms)

Here is the editorial: Editorial

After I read the editorial, which explains the DP solution, I found this line below:

おまけ: 以上の考察をもう少し進めると、この問題は O(NlogN) で解くことが出来ます。

That means there is a faster way to solve this problem.

My friends has just found a NTT solution. It works in O(NlogN).

NTT Solution (2ms)

I hope it will be useful!

Happy coding!

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