Welcome to Codeforces Beta Round #72.
The authors of the round are: Kholkin Pavel, Nikolay Kuznetsov and Kaluzhin Alexander. This round is for both divisions. You will get different problems and we hope that every participant solve as much problems as he can.
Thanks to Rakhov Artyom and Pavel Kuznetsov for their help, Mary Belova for translating problems and Mike Mirzayanov for the perfect system.
The main hero of the problems is Valera. Today you should help him in everything. =)
Good luck and high rating for everyone =)
Upd: the contest is over, congratulations to winners:
in div1 - tourist
in div2 - StelZ40494
Where can I see the changes of my rating in a picture?
Please help me. :)
May I know how do I access the full testcase for testcase 56 problem C? The testcase got cut off halfway :S
Ugh, if I swap the order of 2 of my lines of code, I would have gotten AC for what qn :S
They are back now.
The smaller participant the more rating?
May be because the Yandex contest was a mix of div 1 and div 2 contestants but this is a pure div 1.
May I know how should problem D be done? Here are some ideas I have.
1. K must be prime. If not, the number will have some divisor smaller than K.
2. Suppose K >= 10000. Then, suppose X is a valid number. Then X/K <= 2*10^5. We can check the factors of each X/K up to min(K,sqrt(X/K)). Then the complexity is thus on the order of 10^7.
3. Suppose K <= 10000. I was thinking of applying PIE, but I am not sure how to compute that in a fast manner. :S
Thanks in advance for your help!
important for him. Since the doctor works long hours and she can't get distracted like that after all, she asked you to figure it out.
Russian ones:
http://codeforces.net/blog/entry/1961
http://codeforces.net/blog/entry/1976
http://codeforces.net/blog/entry/1979
Thanks for the links. However, do you know when will the English analysis be ready?