I reached 1500 in Luogu recently. How is this score in Codeforces? How can I improve my thinking level? And how diffuclt problems should I do? Should I do 1600~1800 in Codeforces and green in Luogu？

For all Chinese, I wish you perform better in the CSP Round.

For all foreigners, I wish you perform better next CF Round.

I used toposort, LIS and a priority queue in CF1572A Book

So why it's wrong?

My code:

281581302

If you can hack me, please reply me.

How fast can the CF C++ executer run?

Or how much data can the CF C++ executer run in one second?

Can $$$3*10^8$$$ AC in one second's limit?

Which runs faster,C++11, C++14, C++17, C++20 or C++23?

Please reply me.

Sorry for my horrible English grammar.