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Hey! Check out my video solutions for the contest. I've covered Problem A-G. https://youtu.be/WBECy_7Ux0I

But the rankings is same as before. And my friend’s rating increased but I faced a decrease in rating. Why?

My rating was updated to expert few days ago and today it is showing back to specialist, it has reduced by some points in this contest. Have anyone else faced this?

Your solution 151551197 for the problem 1660C significantly coincides with solutions khnhcodingkarlo/151551197, chungqt/151586274, tahuruzzoha/151586666. I received the above mail this morning. With all due respect sir, I have just started with codeforces and use VS Code to write my own logic and codes, the above allegation to me cannot be justified, I have no clue how my code got out and how did this happen. The first said user 'chungqt' is not even available as a user when I search him on codeforces. As for the second said user 'tahuruzzoha', his solution can be found to have a timestamp of exactly 10:15 pm (IST), the exact time when the contest was ending, whereas my coded solution has a timestamp of 8:53, more than an hour before this user submitted the solution. (Doesn't this seem a bit suspicious why his code was given at the last minute?). My further question stands, if this solution had been leaked publically, (as we know some get out to all public freely or for some money), there would have been not just 2 but 20 same submissions more or else. To further support my case, I even did some comments in my code, and used a set instead of a map because just that morning I had learned that even finding a elements in a set O(logN), which struck me to use it in my code. After the contest I realized that a map would have worked just fine, or even better time complexity wise. If I had cheated, wouldn't I have used a map or same logics and all? There is so much difference between my logic and other 50 codes I have seen past hour now. I don't know how to prove my innocence any further in this case, this has never happened to me, and I don't know what is going to happen next to my id. If anyone wishes to shed some light on this, please help. I seriously have no clue how my code got out. :( That too to just one guy? I don't even know him :( Please help.

Can someone explain to me in a simpler language the solution to problem D? I was able to figure out, that for odd n, a valid answer is always 2, and if n is a power of 2, answer is -1. But I was not able to figure out for even n which are not powers of 2. Can someone help?

The author says that if we have elements with difference 1 along with 1 in the array, such as 1,7,8(eg) we have answer no. But in the case said by you, we get answer yes, as we have no 1 in array as well as no 0. This has been said in the first line of editorial, if there is no 1 in array answer is always yes.