Hello, Codeforces!
I'm quite excited to invite you to participate in Codeforces Round #447 (Div.2 Only) which will be held on November 19 16:55 MSK.
All five problems are created by Zerui Cheng (Marco_L_T), Bingheng Jiang (NOIRP), Yiming Feng (whfym). And it's our first round on Codeforces. We want to show our great thanks to our school The High School Affiliated to Anhui Normal University and our coach Guoping Ye in competitive programming training.
And we also want to show our great appreciation to Mikhail Krivonosov (mike_live), Gleb Lobanov (Glebodin), Weihao Zhu (Tommyr7), Shiqing Lyu (cyand1317) for testing the problems, to Nikolay Kalinin (KAN) for coordination and to Mike Mirzayanov (MikeMirzayanov) for the fantastic Codeforces and Polygon platforms. The round can't be realized without their great help.
The contest will consist of 5 problems and you'll be given 2 hours to solve them. As usual, the scoring will be announced shortly before the start of the contest.
The contest is rated for Div. 2 contestants. And the same as before, Div. 1 contestants can take part out of competition.
Wish everyone high rating and bugless code!
See you on the leaderboard!
Clarification: In the mail, it reads that the duration is 2 hours and 30 minutes and it'll contain 6 problems. There's a mistake. The duration of the contest is 2 hours and there will be 5 problems.
UPD1: Scoring: 500-1000-1500-2000-2500
UPD2: The contest is finished! Have fun hacking!
UPD3: The system test is finished! Congrats to the winners!
And do you find something interesting in the statements,especailly for Chinese contestants?
Div.1 & Div.2:
fateice_ak_ioi (solved all the problems and got 22 hacks)
peace (solved all the problems and got 10 hacks)
KrK (solved all the problems)
Benq (solved all the problems)
Div.2:
fateice_ak_ioi (solved all the problems and got 22 hacks)
peace (solved all the problems and got 10 hacks)
ec24 (made 16 hacks)
UPD4: Maybe you're complaining that there're too many hacks and the pretests are so weak,but it's our intention to do so. We regard hacks as a very important part and a feature of Codeforces.Do you agree?
UPD5: Editorial
Maybe B and C are a little harder than before,we'll be cautious about this next time.
Hope you have fun in solving the problems and hacking!
See you next time!