The courses on edu section are very helpful to learn a topic. It will be much helpful if there is a course on dp on the edu section with practice problems.

I have submitted the following code in c++14, where I used policy based data structure(pbds), which didn't passed due to tle in the system test. In c++17, the result is also tle.
problem link: https://mirror.codeforces.com/contest/1794/problem/C
submission link:https://mirror.codeforces.com/contest/1794/submission/196039857

But I submitted the same code with c++20(64 bit, winlibs) and got accepted.
submission link: https://mirror.codeforces.com/contest/1794/submission/196061031

What is the reason? Can anyone help?