By RAD, 8 years ago, translation, ,
Good evening

Yesterday evening the Saratov university delegation returned from St. Petersburg, from the ACM-ICPC NEERC 2010/11 World Programming Championship semi-finals. If you haven't seen the final standings: 4 Saratov teams received diplomas, and we (Saratov SU 2) advanced to the finals. Saratov SU 1 was also among those, who advanced, that's pretty cool for their first time, but didn't advance because of the limitation "only one team from one university".

Also we have prepared a Div. 2 round. Thanks for prompt assistance to Edvard Davtyan, Gerald Agapov and Maria Belova.

Good luck!
Artem Rakhov and Codeforces team

Unfortunately, the discrepancy between author’s solution and statement of problem E was detected. We bring our apologies to all the participants. All solutions that have not been Accepted previously were rejudged. Thanks to member xcr for detection of the issue.

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 8 years ago, # |   +1 Someone can paste the Pretest #6 for the problem D?I can't figure what is the problem with my solution...
•  8 years ago, # ^ |   0 Try 1 2 and 1 4
•  8 years ago, # ^ |   0 He means pretest?1 2 and 1 4 are used for hack.
•  8 years ago, # ^ |   0 Ah, yeah, sorry
•  8 years ago, # ^ |   0 У меня бага в 1 4 оказалась. Айайай как обидно, что во время контеста не догадался его вбить.
 8 years ago, # | ← Rev. 2 →   0 / a.out 1 201 11 21 1./a.out 1 411 4 1 11 11 21 31 41 1
•  8 years ago, # ^ |   0 Try these tests: 4 4 , 4 5 , 5 4 , 5 5 (all the rest cases).
 8 years ago, # | ← Rev. 2 →   0 I wonder if it wouldn't be better to have a possibility to lock the problem and start hacking without passing pretests, even without submiting it.
•  8 years ago, # ^ |   +1 I think it wouldn't be better, because in your case contestant can use 2 accounts: one for stealing solutions from another, second - for submitting stolen solutions. Now for getting solutions from competitors, even cheater have to write solution which passes pretests
 8 years ago, # |   0 How do I prove for problem D that when both n and m are odd, we can't find a required path without using teleporting gates?
•  8 years ago, # ^ |   0 Well, let's look at board painting. Every turn we change color of cell, in which king stays. So, for odd n and m cell at n*m turn will be black. n*m+1 turn must follow us to (1,1), which is also black. So we're used to place at least one gate.
•  5 months ago, # ^ |   0 In the above comment, the board painting refers to visualizing the board as a chess board with the cell at (1, 1) being colored black.
 8 years ago, # |   0 Give me 23 test for E, please
•  8 years ago, # ^ |   +2 Big random test with 99 cars, and 100 segments for each car.
•  8 years ago, # ^ |   0 thanks
 8 years ago, # |   0 What's final test 25 at problem D? Thanks..
•  8 years ago, # ^ | ← Rev. 8 →   0 I don't know. But I can assure you that if your code passes the following types of inputs, it should pass all the inputs,odd eveneven oddeven evenodd odd1 22 1thanks to HackSon.
•  8 years ago, # ^ |   +1 I think "1 even" and "even 1" are not precise enough...1 22 11 MN 1where N, M > 2.
•  8 years ago, # ^ |   0 it's unnecessary to check "1 M" and "N 1" when N or M odd since it same as "odd odd"
•  8 years ago, # ^ | ← Rev. 2 →   0 I have it done more complicately, so it's giving me Time exceeded.. but i think it should handle it for every 1<=n, m<=100
•  8 years ago, # ^ |   0 99 99
 8 years ago, # |   +6 Hi to codeforces team why you don't put test case's and problem's(in PDF) after each contest ?it's usefull for every one ....thanks for attention
 8 years ago, # |   0 Congrats on making into the finals!! 9 Problems done, that is pretty impresive.
 8 years ago, # |   0 Today I participated "out of competition". I have 2 questions:-My solution got hacked by another div1 contestant. So....does this mean I'm able to hack any other div1 competitors? Cause I didn't see any one in my "room".-Am I able to see the case that got me hacked during competition?Thx in advance
•  8 years ago, # ^ |   0 To see other "out of competition" contestants in your room you should check box, that doing it (in top right corner).Hack protocols availible at "Hacks" tab by link in "Verdict" column.
•  8 years ago, # ^ |   0 If you participate 'out of competition', then when you enter the contest you appear in room number 1 instead of the room you were assigned to. (It's a bug.) To move into your room, select it from listbox in top right corner, it's marked with a star.
 8 years ago, # |   0 Can anyone explain me problem C, I couldn't program it and ended up getting -2, how about a contest analysis after every contest?
•  8 years ago, # ^ | ← Rev. 2 →   0 Let C[i] = # of integers in A1...AN s.t. Ak = i (mod 3)Then answer = C[0]/2 + min(C[1], C[2])
•  8 years ago, # ^ |   +1 Previous explanation is for problem B. As regards C you just have to pair numbers a, b when:a % 3 = b % 3 = 0 or a % 3 = 1 and b % 3 = 2. In such cases (a + b) % 3 = 0.
 8 years ago, # |   0 Hi.. Can you give me the case no.3 from problem D? Thanks..
 » 4 years ago, # |   0 can somebody tell me why using b as a char array works just fine but defining it as char* gives wrong answer??(c code)here is the wrong answer code