What is the difference between C++20 and C++17 ?

I have submitted two solutions for the problem B. Points on Plane in Educational Codeforces Round 145 (Rated for Div. 2).

the first sumbmission for the problem in C++20(64) and I got a WA 198792748.

However I tried C++17 and got AC 198792971.

I need a clarification for this situation ,please.

Thanks for help!