Solution Link of number C question https://youtu.be/PK27JkDUq58
Some cheater
https://mirror.codeforces.com/contest/1822/submission/203341284
https://mirror.codeforces.com/contest/1822/submission/203341760
https://mirror.codeforces.com/contest/1822/submission/203337437
https://mirror.codeforces.com/contest/1822/submission/203339721
https://mirror.codeforces.com/contest/1822/submission/203337206
https://mirror.codeforces.com/contest/1822/submission/203338592
https://mirror.codeforces.com/contest/1822/submission/203337275
https://mirror.codeforces.com/contest/1822/submission/203337979
https://mirror.codeforces.com/contest/1822/submission/203339037
https://mirror.codeforces.com/contest/1822/submission/203340194
https://mirror.codeforces.com/contest/1822/submission/203333829
https://mirror.codeforces.com/contest/1822/submission/203331409
https://mirror.codeforces.com/contest/1822/submission/203338800
https://mirror.codeforces.com/contest/1822/submission/203343647
https://mirror.codeforces.com/contest/1822/submission/203334186
All of them submit solution after video published in youtube. MikeMirzayanov take action against them.