I got a FST in Div1B.

But when I submit the code again after contest , it accepted (but 1981ms).

And when I submit the same code again with C++17(64) , it accepted and only ran 1653ms.

What a pity...

My submisson during contest:109857178

Submisson after contest:109891513

With C++17(64):109891826

When I was generating datas, I couldn't imagine the strange solutions for this problem. So I didn't know how to generating strong datas :(

Sorry for that:(

Yes of course. In fact $$$9n^2$$$ is easy too, and I think there should be a $$$n\log^2$$$ solution.

Great!It will make codeforces better. :D

$$$\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$$