Hello, Codeforces!
Educational Codeforces Round 15 will take place on 29 July 2016 at 18:00 MSK for the first and the second divisions.
The round will be unrated for all users and it will be held with extented ACM ICPC rules. You will have two hours to solve six problems. After that you will have one day to hack any solution you want. You will have access to copy any solution and test it locally.
We with Mike MikeMirzayanov Mirzayanov decided to prepare this Round, because Edvard Edvard Davtyan is very busy at his new job. Good luck and have fun!
UPD Competition completed! Thank you all! Editorial
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This is unrated for all user meant?
Of course.
Where is Edvard ?
"because Edvard Edvard Davtyan is very busy at his new job"
In the mountains.
CF contest no 702. If we truncate trailing even digits, we would get lucky 7!
Hope everyone get points multiple of 702!
(Do not see rev 1, it was a mistake!)
It is number 702.
Ow! You are seeing too old version, see the updated revision!
hello
hi! its time to start the contest. So, do not waste time now!
in B in the first example shouldn't the pairs of indices included in answer be: (1, 4) and (2, 4) instead of (1, 4) and (3, 4)?
No,it shouldn't :D
Will we be able to see the tests before hacking period ends?
YSE
Well, i found out that my first submission is incorrect, so i resubmited but its still showing the first submission
and it shows hack it for both submission too .. i wonder what happen if someone got successful hack on the old one
Has anyone tried solving D using a binary search?
I`ve tried with ternary search, but WA on test 22 :(
My ternary search also failed, but then I checked for 100000 values on left and 100000 values on right of the result of ternary search and it passed :)
https://codeforces.me/contest/702/submission/55383837
Solution with ternary search
How is it my solution for D with map runs in 200 ms but solution with multiset gets TLE (>3000 ms)?
multiset: 19483894
map: 19499476
Is multiset really so slow? Why?
complexity of
multiset.count(value)
is not O(log(N)) but O(log(N) + Count).Oh. Thanks.
I downvoted every single comments:D
But you cannot vote for your comments.
nice life you have there m8
Got "unexpected verdict" in hack 245453, 245473 and 245477.
And 245205 too.
Fixed.
thank you
How to solve problem C if all the points were on 2 dimensional plane?
With k-d trees a straightforward is possible, is there another/better solution?
Hmm. Deleted.
Hi,
In this this round, I've tried to hack the others code in hacking phase; but I couldn't find any buggy code or some tricky test case to hack and I've finished with an unsuccessful hacking attempt! After this try, I noticed that I should have a suitable mechanism for hacking. So what's your idea about it? what's your suggestion for me to do better in hacking phase?
And here my questions about hacking:
I would also like if someone replies on this.
This is a good question! I've faced to this event and It's my question too. So I'm waiting for the answer...
any hint about problem E or link please !!
Read about sparse tables in topcoder and everything will seem simple.
problem E hint please
Why for the first testcase the output is 3 not 4 The increasing sequence can be 1 2 11 15 or 1 7 11 15