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### P___'s blog

By P___, history, 9 months ago, ,

Hi,

Since nobody has mentioned this SRM, I do that here:

Time.

I am not the author, just want to increase the number of participants.

Thanks!

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 » 9 months ago, # |   0 Can anyone tell me what can be done when the applet says "A connection to the server cannot be established" when I try to login? I tried autodetect, it doesn't work. It was working well a few weeks back.
•  » » 9 months ago, # ^ |   0 download the applet again. usually works for me.
•  » » » 9 months ago, # ^ |   0 Tried that. Still doesn't work :|
 » 9 months ago, # | ← Rev. 2 →   +11 Thank you so much for posting this! I always miss SRMs, and finally get to compete in one. GLHF everyone!
 » 9 months ago, # |   +38 Does anyone have proved solution for 1000?
 » 9 months ago, # |   0 How to solve medium? (I have O(k3) with small constant which gets AC in 1.6s)
•  » » 9 months ago, # ^ | ← Rev. 5 →   +21 upi is an expected sum of heights of nodes in tree with i nodes.dpi is an expected sum of length of paths in tree with i nodes. by linearity of expectation.Similary, because sum of length is sum of length in both subtrees and sum of length of paths going through root.
 » 9 months ago, # |   +25 About Div1 Hard.My solution was to look at only Pareto-optimal choices. First, we sort the friends by decreasing number of bits set. After that, we recursively pick or kick them in that order. The single important check which makes it run faster than like 2568 is as follows: if we kick a friend X, we also have to kick all further friends which have a subset of X's skills (otherwise, the choice wouldn't be Pareto-optimal).In practice run, this takes <100ms on all the given tests. Can someone please either construct a test where this becomes slow, or prove a reasonable asymptotic bound for the number of Pareto-optimal choices?
•  » » 9 months ago, # ^ | ← Rev. 3 →   +13 What about all (C(8, 4)) masks with 4 bits? Then it will be like 708?
•  » » » 9 months ago, # ^ |   +10 Challenge succeeded :) .A pity you were not in my room.
•  » » » » 9 months ago, # ^ |   +16 I wanted to challenge you with this exact test..However, I was so stupid that I did not know paste in TC is ctrl+v (while in macOS is it command + v). :P
•  » » 9 months ago, # ^ |   +1 On all vectors with 4 1-bits out of 8 it will be 708 / 8! ≈ 1010
 » 9 months ago, # |   0 can someone explain how to solve "div1 easy"? making second tree by removing edge from first tree.
 » 9 months ago, # |   +1 how to solve div2b