IZhO 2020 is finished. You can find final results here.(only participants who won medals are included)
A week is left till IZhO 2020! I think it would be great to make a list of participants with their names and codeforces profiles. So, please, leave in the comments list of the participants you know will come. Also, what are your predictions?
| № | Пользователь | Рейтинг |
|---|---|---|
| 1 | Benq | 3676 |
| 2 | jiangly | 3670 |
| 3 | Kevin114514 | 3657 |
| 4 | maroonrk | 3355 |
| 5 | Um_nik | 3353 |
| 6 | squareOf105 | 3346 |
| 7 | tourist | 3343 |
| 8 | strapple | 3324 |
| 9 | heuristica | 3322 |
| 10 | jiangbowen | 3291 |
| Страны | Города | Организации | Всё → |
| № | Пользователь | Вклад |
|---|---|---|
| 1 | Qingyu | 158 |
| 2 | nik_exists | 150 |
| 2 | maspy | 150 |
| 4 | AmShZ | 143 |
| 5 | Um_nik | 141 |
| 6 | Errichto | 139 |
| 7 | adamant | 137 |
| 8 | BledDest | 133 |
| 8 | maroonrk | 133 |
| 10 | qwexd | 130 |
some participants from Armenia
Aleksandr Abelyan enoone
Samvel Andreasyan Andreasyan
Davit Margaryan DavitMarg
Emil Kostanyan EmilConst
Robert Kocharyan 312352145215
Rafayel Susanyan gRaphael
Narek Beglaryan BegNar
Arayi Khalatyan Arayi (but in math team :D)
some participants from India
antontrygubO_o
AmShZ
Petr
summitwei (orz)
Also what are your predictions for the winner? I think top 5 will look like summitwei, summitwei, summitwei, summitwei and summitwei.
I think bruhh will win again.
Will Benq participate?
No, he's ( bruhh ) decided to try his forces in math this time.
I think top 5 will look like enoone, enoone, enoone, enoone and enoone.
Who are you? XD
I am your fan
I am your fan
I'm your father.
Bro 300iq is joining this year...
Really?
Unfortunately, I won't go :(
why?? :(
It's just too easy for him :(
OMG< WHY ???????????????????????????? I AM YOUR FAN PLEASE
Some participants from Georgia:
achi_basadzishvili
lukamosiashvili
GioChkhaidze
David-M
Some participants from Georgia:
David-M David Memarnishvili
achi_basadzishvili Achi Basadzishvili
lukamosiashvili Luka Mosiashvili
GioChkhaidze George Chkhaidze
Ana2003Maisuradze Ana Maisuradze
temoyanteladze Teimuraz Kanteladze
Beso.Managadze Besarion Managadze
I am the biggest fan of temoyanteladze
All for informatics?
Yes, of course. If there is an interest in Math competitors I can also provide their handles.
yes, pleasee
Some participants in Math from Georgia:
bruhh Nikoloz Birkadze
Temotoloraia Teimuraz Toloraia
tkorkotashvili Tamar Korkotashvili
anaonofrishvili Ana Onofrishvili
Lkvatashidze Lasha Kvatashidze
Tekor is No.1!
If anyone knows, will there be an online mirror anywhere?
Maybe Tima knows something...
I think lukamosiashvili will win
sameeeee
Guys, lets go make codeforces-bet system to turn our predictions into money.
Some participants from Kazakhstan:
Temirlan Baibolov bthero
Adilkhan Muratov paradox
Dalen Amir Dalenator
Amanbol Kanatuly amanbol
Ildar Kanaliev IldarKA
Parasat Kyzyrkanov Fortitude
Kamzabek Narkhan nkamzabek
Almaz Shinbay shinbay
Yaroslav Kim ThatDude
Rakhman Afra1d
Ali Soldatbay imandy_bolsyn
Nuradil Zhambyl prudent
Andrey Genze Evilandrew
Alim Imanmalik alimq
Timur Ratnikov Thanos234
Noel Muhamedjanov noelkawm
Dmitriy Mazylo ghoast
Dimash Tursynbay DimmyT
hello there
Team from Novosibirk FairyWinx, Pechalka
Ukraine participants anakib1 mmanvelyan
Participants from Turkmenistan:
Suleyman Atayev — Suleyman.A
Gurban Gulladyvev — Gurban
Dovran Akmyradov — Dovran
Merdan Muradov — Muradow
GL to everyone
I think Nodir_Bobiev will win.
Also, where can be found results of previous years?
2017 2018 2019
Tudor Vianu National High School's team:
Tiberiu
apostoldaniel854
participants from Chelyabinsk: 74TrAkToR AlFlen
I think 74TrAkToR or AlFlen will win.
Good luck!!!
Have fun
I added a rank list based on CF rating.
plz add maxflow aka Maxim Khabarov
Есть ли возможность посмотреть результаты?
Maybe anyone from Almaty can sand results of first day. Who can do it?
The results for day 1 can be found here : https://izho.kz/contest/results/
I assume the day 2 results also will be there shortly
Anyone remembers the last year's cut-offs?
The only thing I remember is that the gold started from 14th place since I was second seilver at 16th place. As I can see you are 15th now, so I hope this year there are more golds than last year. Good luck! :)
Let's see what happens. Hope they also consider point differences. Thank you!
Hey guys, our team is doing some team results calculations and we're wondering how other teams did. Could you let us know? Our (Serbian) team had 346 285 in CS, 32 30 28 in Math and 29.5 21.7 in Physics.
Grand Prix)
How to solve the problem F?
Statement: N numbers and Q queries are given. For each query we have l and r, and we erase all the numbers from the array that are not in range [l, r] (i.e. only keep numbers with l<=ai<=r). You need to find the sum of the absolute differences of each adjacent remaining elements. Note that all queries are independent.
Mo's + set doesn't give any points for other than quadratic subtask and one easy special case. I tried to optimize it but still got nothing (even n,q<=50000 doesn't pass). That surely was because of many set operations and their big constant factors. However, I implemented some set-like data structure (don't know if it exists or maybe it's just rb-tree idk) with good constant factor and managed to pass all except the n,q<=2*10^5 subtask.
Let's divide the array on blocks length $$$\sqrt{n}$$$. For each block we will calculate the following values:
$$$dp(l,r)$$$ — the sum of the absolute differences of each adjacent elements if we leave only numbers in range $$$[l,r]$$$. We consider only for those $$$l,r$$$ that occurs in the block.
$$$first(l,r)$$$ — the leftmost element in range $$$[l,r]$$$.
$$$last(l,r)$$$ — the rightmost element in range $$$[l,r]$$$.
$$$next(i)$$$ — the minimum value in this block is greater than or equal to $$$i$$$.
$$$prev(i)$$$ — the maximum value in this block is less than or equal to $$$i$$$.
If we know these values, it will be easy to calculate the answer for each queries.
Firstly, we will calculate with brute force $$$dp(l,max)$$$. Then one by one we wil remove the maximal element from the remaining elements. We can delete each number in $$$O(1)$$$ with something like Linked list.
Time complexity: $$$O(n \sqrt{n})$$$, memory: $$$O(n)$$$.
UPD. Code
Too bad it isn't sum of non-absolute differences.
if you still alive, can you share your own implemented set-like data structure? ordered set has too big constant factor.
Good news: I am still alive.
Bad news: I remember not much of it. I think it might have been a cache-friendly B-tree implementation. My performance engineering knowledge back then was pretty shallow, so I probably tried out a few tricks until one magically worked out.
Nowadays, you can actually get huge improvements over std::set by using custom SIMD to cut cycles off as much as possible. One implementation that has 18x lower_bound speedup compared to std::set is public [1]; there are slightly more performant options but they tend to be CPU-targeted.
[1] https://en.algorithmica.org/hpc/data-structures/b-tree/
You can find the problems here.
Day 2 contest not in IOI format
Done.
Where can I find dnadict.zip?
How to solve the problem C?
Can somebody please share their solution for problem A,B,C please, or at least the code, thank you.
Solutions to all problems
Thank you veryy much!!
May be ojuz can add this contest to their website so that people could share their solutions there please.
Lots of people have been asking me to add IZhO problems.
Sorry but I can't do that, because there are no contest materials from their official homepage: https://izho.kz/contest/problems/
Hope this comment reduces the amount of IZhO requests..
Oh, ok. I thought you could contact the organizers somehow, thank you anyway.
How did you add last year's problems??
That's a good question.
A user asked me to add IZhO 2019 tasks with the tests package. I hope every request be like that.