### rng_58's blog

By rng_58, history, 3 months ago, ,

We will hold Dwango Programming Contest 6th.

The point values will be announced later.

We are looking forward to your participation!

• +123

 » 3 months ago, # |   0 Hope this contest isnt unrated too.
 » 3 months ago, # |   +4 How do you solve task B? I didn't even understand the statement.
•  » » 3 months ago, # ^ |   0 Editorial of A, B are available.
•  » » » 3 months ago, # ^ |   0 can you explain the editorial of B ?
 » 3 months ago, # |   +6 How to solve D?
•  » » 3 months ago, # ^ | ← Rev. 2 →   +22 I was adding numbers one by one from postion $1$ to position $n$. Let's say we are adding currently element at position $i$ (there is $n-i+1$ possible values). In case some element can not be right for all other elements (rest $n-i$ elements have same $a_i$ value), then put that element on position $i$. Otherwise put smallest or second smallest element on position $i$. Obviously we can not get smaller lex permutation than this one, but also it is possible that last two elements are bad in the permutation:For example case:$n = 5$$a = [2, 3, 1, 5, 4]$My algorithm will give result: $[1, 3, 2, 4, 5]$ and it is incorrect result. But we can make it better, just pick last three elements and try every permutation — at least one of permatutions will be valid (that is reason because there is no answer just for $n = 2$).
 » 3 months ago, # |   -64 I would had much apreciated to get a "warning" or something before haveing submitted A. Because then I would had read the other problems beforehand, and propably would not have participated at all.
 » 3 months ago, # |   +8 How to solve C?
•  » » 3 months ago, # ^ | ← Rev. 2 →   0 There is an editorial available. editorialEdit: Just saw that the english version is not available for all problems, sorry.
•  » » 3 months ago, # ^ |   0 Here's a nice analogy: you can interpret the problem as follows- There's a $k\times n$ grid. First you have to distribute $a_i$ black hokey pucks among the $n$ cells of the $i$-th row (for each $i$). Then you have to distribute $n$ red hockey pucks on top of the $\sum a_i$ black pucks such that every column has exactly one red puck. Count how many ways are there to do that.
 » 3 months ago, # |   +3 How to solve B , i did not understood the editorial
 » 3 months ago, # |   +10 Did it say that the English version of the Editorial would come out today?
•  » » 3 months ago, # ^ |   0 I still don't know how to solve C
•  » » » 3 months ago, # ^ |   0 If you get it from somewhere or translate and understand using the Google-Translate Api then please share it here.
 » 3 months ago, # |   +8 Hi, it's been more than a day and the editorials are not out, as promised. It would be great if you could upload them since the questions were interesting :)
•  » » 3 months ago, # ^ |   0 editorial is out already .... on yesterday
•  » » » 3 months ago, # ^ |   0 The English one for the later problems isn't.
 » 3 months ago, # |   0 In problem B editorial how to prove the probabilities stated are correct. For example it is given In order for Slime i − 2 to cover the section from xi to xi+1, both Slime i − 1 and i need to be chosen earlier than Slime i − 2, so pi,i = 1/3. How to prove it ?
 » 3 months ago, # |   0 Where can we see the data? I found that it isn't in the dropbox...
 » 3 months ago, # | ← Rev. 2 →   0 can someone please explain the solution for problem C? I am not able to understand tutorial for the problem