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?~~

some participants from Armenia

Aleksandr Abelyan MrDecomposition

Samvel Andreasyan Andreasyan

Davit Margaryan DavitMarg

Emil Kostanyan EmilConst

Robert Kocharyan rkocharyan

Rafayel Susanyan Wish_Performer

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 saba2000 will win again.

Will Benq participate?

No, he's ( saba2000 ) decided to try his forces in math this time.

I think top 5 will look like MrDecomposition, MrDecomposition, MrDecomposition, MrDecomposition and MrDecomposition.

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:

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:

saba2000 Nikoloz Birkadze

Temotoloraia Teimuraz Toloraia

tkorkotashvili Tamar Korkotashvili

anaonofrishvili Ana Onofrishvili

Lkvatashidze Lasha Kvatashidze

YaKonchil 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 Dalimus

Amanbol Kanatuly IIeJlMeHb

Ildar Kanaliev MAHTbl

Parasat Kyzyrkanov parasat

Kamzabek Narkhan RedDreamer

Almaz Shinbay Shinbai

Yaroslav Kim ThatDude

Rakhman Rakhman

Ali Soldatbay Aslead

Nuradil Zhambyl deepwork

Andrey Genze evilandrew

Alim Imanmalik alimq

Timur Ratnikov Thanos234

Noel Muhamedjanov noelcowm

Dmitriy Mazylo ghoast

Dimash Tursynbay DimmyT

hello there

Team from Novosibirk -____-, Pechalka

Ukraine participants anakib1 mmanvelyan

Participants from Turkmenistan:

Suleyman Atayev — Suleyman.A

Gurban Gulladyvev — Gurban

Dovran Akmyradov — Dovran

Merdan Muradov — Muradow

GL to everyone

Also, where can be found results of previous years?

2017 2018 2019

Tudor Vianu National High School's team:

Tiberiu

apostoldaniel854

participants from Chelyabinsk: tractor74.ru AlFlen

I think tractor74.ru or AlFlen will win.

Good luck!!!

Have fun

I added a rank list based on CF rating.

plz add LinusTorvaldsFan aka Maxim Khabarov

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.

solutionLet'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.

How to calculate dp(l,r)?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.CodeToo bad it isn't sum of non-absolute differences.

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.