Codeforces Round #919 D is very similar to https://mirror.codeforces.com/contest/381/problem/C. I noticed this whilst in the round , but i submitted the correct answer after the system test.Correcting the input format and a very simple modification to the code i sent previously got accepted.
My Submission to Codeforces Round #919 D : https://mirror.codeforces.com/contest/1920/submission/241490363
My Submission to Codeforces Round #223 C : https://mirror.codeforces.com/contest/381/submission/222796358
Note that this is not a proposal to make the round unrated.