Gone crazy while solving problem 1874E - Jellyfish and Hack. I optimized my solution with best effort, and its execution time decreased from 20s at first to about 6s now (locally), but it got TLE on codeforces (time limit 8s).

When I was wondering how small the constant could be to pass the problem, I realized that I submitted with C++17(32), and I wanted to switch the language into C++17(64), but where is it???

What's more annoying is that almost all accepted submissions to this problem used C++17(64), mostly with an execution time longer than half of the time limit, so I think this problem can hardly be passed without C++17(64).

When can we have our C++17(64) back?

In the last round #850, when solving problem D of div.1 1785D - Деревянная ложка, I submitted the code with language C++17, using fast fourier transformation (although it's not the intended solution, but its time complexity is correct), but it gave TLE on pretest 20 (which is $$$n=20$$$).

After the contest, I resubmitted the same code with language C++20, and it shown Accepted with the execution time of only 1434ms! So I wonder why there's such a big difference between these two languages, and I want to know whether I can request a rejudge in such kind of situations.

Here's the submission link: C++17 192349326 C++20 192414277