then how to practice in range 1100-1500 ?

you are right !! Then the only option left is to gain 2 years of experience at a company where you actually learn dev stuff and then try switching to these big MNCs or established startups (which don't hire good talents due to diversity hiring). All the diversity hiring agenda goes in trash when hiring for experienced developers

no way I still believe that number (5-10%) is good estimate. Just a guesstimate approx. 20-30k students pursue CS/IT from engineering colleges every year. And only 2000-3000 people actually get themselves truly involved into cp (not including those who aim for DSA from sources like GFG and Leetcode)

isn't this link directing to page written in Korean ? Are problems available in English language at this website or we will have to use google translate ?

Hi there sav I have been working upon dark mode for the Codeforces to accommodate features like testcase highlighting and overall provide a newer look to the platform. Will you be interested in reviewing it ?

I have an explanation for the 1st problem, do you still need it ?

Ertugrul onebit1024, the reason I chose yellow was it was a little less vibrant color in comparison to white, thus more soothing for eyes to read.

I have a solution though, I will post another theme screenshot having violet and white. If that will get better response, then I will make the required changes.

btw why are there so many downvotes ?
Is there something wrong with the theme, or it's something else ?

it's still in development phase, I will try to finish it asap

Hey T1duS and all other viewers, lately these days I have been trying to develop a dark theme for CodeForces from scratch. Below I m sharing links to sub-components that I have touched upon so far:
- Basic Theme: link1 (dark violet and yellow)
- Test-case Highlighting: link2
- Button-hover Bubble Effect: original vs my-Substitute

Hey there Ertugrul coderdhanraj haochenkang onebit1024 and everyone else who has been following this comment thread.

I m here to update you guys with what I have worked upon till now regd. dark theme :
This is the theme( fixed MathJax text colour ): Take a look
And here is the cool test-case highlighting: Take a look
Lastly I updated button-hover bubble effect, couldn't replicate the original animation so injected my own : Take a look- My version vs Original
Hope you will all like it :)

NOTE : text-colour of MathJax generated text is white since, I thought it would help differentiate the MathJax text from rest of the text in a problem and thus, grab our attention towards them quickly during a live contest problem.

It's due to text generated from mathJax. I will surely fix it !!

Besides is it looking good enough to be a pleasing-to-use dark mode ?

I m planning to develop this theme
Looks interesting ?

Hey I m also wondering to contribute on CodeForces by making a dark mode theme in near future. Most probably it be a Tampermonkey script.

Hey I m also wondering to contribute on CodeForces by making a dark mode theme in near future. Most probably it be a Tampermonkey script.

tgp07 Can You help where my approach went wrong in problem F ? My basic idea was to reduce every number in array A and B to their largest odd factors (by dividing them 2 as long as possible) and store the values in two different multisets.
First multiset contains all reduced values of array A.
The second multiset contains all the reduced values present in array B. Then I would simply iterate over the second multiset and for each value in this multiset I will check if there is a matching value in first multiset.
If yes then I will delete that value from first multiset else I will further reduce this element further by 2 and again try to match with first multiset as long as this element is > 0. >br> After iterating over all values of 2nd multiset, if first multiset is empty then my answer is YES, otherwise it is NO.

UPDATE : I figured out the issue, which was due to continue statement in one of my while loops.
The wrong submission here

Hey Edlue Can You help where my approach went wrong in problem F ? My basic idea was to reduce every number in array A and B to their largest odd factors (by dividing them 2 as long as possible) and store the values in two different multisets.
First multiset contains all reduced values of array A.
The second multiset contains all the reduced values present in array B. Then I would simply iterate over the second multiset and for each value in this multiset I will check if there is a matching value in first multiset.
If yes then I will delete that value from first multiset else I will further reduce this element further by 2 and again try to match with first multiset as long as this element is > 0. >br> After iterating over all values of 2nd multiset, if first multiset is empty then my answer is YES, otherwise it is NO.

UPDATE : I figured out the issue, which was due to continue statement in one of my while loops.
My wrong submission here

The recent problem from starters 51 (Chef & Cook Game) was more specifically a variation of Nimble Game, which in itself is a variation of Game of Nim.

Here is what I thought would work but didn't pass more than one test-case, Can you explain why was it wrong ??

My approach was very simple : Find the first occurrence of smallest decimal digit present in the string, then remove chars from the string, required to make one instance of this decimal digit. This decimal number will be my most significant digit, thus I will append this digit once in my ans string.
Now from the leftover string, I will try to form as many zeroes as possible. then append this decimal '0' in my ans string as many times as possible.
Now finally, I will iterate from one to nine and try to form as many digits as possible for each one of them in the ascending order and keep appending these digits as the end of my ans string

For Example : str = rzerotwooneonezerofo
Approach : I will first find the smallest possible digit that can be formed (except '0') which is '1' Then I will try to form as many '0's as possible, and finally in increasing order from '1' to '9' form as many instances as possible.
Expected Output : '10012'

Can someone kindly explain how to do digit mapping problem ?

My approach was very simple : find the first occurrence of smallest decimal digit present in the string, then remove chars from the string, required to make one instance of this decimal digit. This decimal number will be my most significant digit, thus I will append this digit once in my ans string.
Now from the leftover string, I will try to form as many zeroes as possible. then append this decimal '0' in my ans string as many times as possible.
Now finally, I will iterate from one to nine and try to form as many digits as possible for each one of them in the ascending order and keep appending these digits as the end of my ans string

For Example : str = rzerotwooneonezerofo
Approach : I will first find the smallest possible digit that can be formed (except '0') which is '1' Then I will try to form as many '0's as possible, and finally in increasing order from '1' to '9' form as many instances as possible.
Expected Output : '10012'

was it on-campus OA ?

I have a variation of this problem whose statement is as follows :
You are given an array of int values, of length N. For a subarray it's score is defined as xor of all elements present in the subarray. Your goal is to choose any two non-overlapping subarrays such that sum of their scores is maximum possible. Print the maximum sum.

How will You solve this problem ?

Note: By non overlapping i mean : 0<=i1<=j1<i2<=j2<N

Thanks a lot for quick response !!

I will try do the backward proof myself, if get stuck then I'll drop a comment, appreciate your effort.

Then this minimum is possible if and only if k≤N−k. More intuitively, there

suppose k < N — k , to remove these k elements (of highest frequency) we will need another k diff elements (which will be present in this case). After removal we will be left with N — 2*k elements.
My question is, for these remaining elements will it always be guaranteed that we can keep forming a pair of two distinct elements and thus make the arr empty in ceil [ (N-2*k)/2 ] moves ??

I updated my point,

Majority of the girls (at our pace) who get hired through this process had equal opportunity right up to the point of entering some university

I still think you didn't get the main point of this thread, Gregory.

Suppose there is a software company that requires to hire 20 developers. A pool of 100 people applied there, from which 50 were men and 50 were women. The company decided to create two separate pools based on gender and then conducted the hiring test/interviews separately for both the pools. As a result, the company hired 13 men from pool A and 7 women from pool B.
Later the company found that the men who were ranked at 14th to 20th place had significantly better scores compared to the top 7 performers of the women's pool.
Then, won't this be injustice to snatch away the opportunity from those 7 men (ranking 14th to 20th in men's pool) and giving it to those top 7 women from pool B, that too for the post of developers ?

By the way, I can assure you with some surety, majority of the girls (at our pace) who get hired through this process had equal opportunity right up to the point of entering some university, now if still they aren't competent enough compared to some men at same uni, why should those women be offered developer jobs in-place of better male students (who get rejected on basis of gender), that is the injustice we are talking about.

hey Termii !!

Everyone approves that women should have equal rights. But most people don't know what that even means...

sadly you can't use it anymore if u can't pay for the monthly subscription !!

variety-jones I was planning you drop a request to kindly increase number of free tickets for a user from 1 to 3 or 4 per 24h cycle.
Hey, but why did u also remove the 1 free ticket that was available to users in every 24hr ?

But why would product based companies hire large number of females that are not having adequate amount of dev/CP knowledge, in place of male candidates who have better knowledge? Wouldn't this hamper the companies' growth and productivity ?

It's CARROT extension which I personally feel is more accurate than Cf predictor. Here is the chrome extension link

thnx for helping

Correct me if I am wrong, but isn't it supposed to show me the list of contests that I gave virtually ??

for example I had participated in couple of div2 rounds virtually, but here in my unrated contest's list no such contest is showing up.

I'm glad that we now have each user's unofficial contests history.

I m sorry but can someone teach me, how to check our unofficial past contests ?

My mistake, I knew about this extension, actually I wanted to know how to use virtual rating predictor from this website : https://cfviz.netlify.app/virtual-rating-change.html

And how much accurate is this virtual rating predictor ?

Can you explain how to use CF-rating predictor ? idk how to use it

vkgainz would you mind explaining/sharing a blog that explains, how to check our seeds in a contest which is about to start ?

Just a suggestion

SOHAG_007 Also try to simulate the contest environment while solving. Because it usually happens with me that I m unable to solve contest problems these days which I m capable of solving and rather solve them later on my own with free mind (no fear of ranking or rating drop/jump) under decent time constraints

To all those people who shelled out Rs.3000($40) into this guy's pocket (Babbar), I would like to give a great advice to you all, just refer to these youtubers :

feature request : A way user can keep track of time taken on each problem solved. Also a time parameter to compare user's personal time with average time consumed by contestants on the same problem.

The_stD7 feature request :

Can we have the feature of comparing our timing on a problem with average/median time taken by contest's participants on that problem.

whohet how can we change/edit Class Completions ? suppose I want sort to sort (arr, arr + n) how can I do that ??

Also how to edit settings file to get vec to vector<>

Rushroom what's O3 and Ofast ?? how to use them in an IDE ?

worked now, thanks

not working argument list for class template "std::numeric_limits" is missing

Jatana how can we change/edit Class Completions ?

did you find what you were looking for ?

can you elaborate on how o install and use it ?

how can we participate in an already finished contest like contest #7

https://codeforces.me/blog/entry/92162

GhostShafi Check his blog

phattd Are you planning to push the feature of atcoder support in near future ?

And suddenly we're ending up with atrocities like 1615D — X(or)-mas Tree. Parity of popcount of xor on paths on tree, really?

kpw29 does that mean that developing intuition for this problem was quite hard or something else??

Hi AnandOza ! right now I m watching your custom number theory problems video on youtube. Nice problems!! [though have got stuck at E and F]

will you be doing more such videos, like custom problems on some other crucial topics and maybe theory streams ?

can you somehow work on your nice project to further provide a color palette like above screenshot as a side option ?

It's color palette doesn't matches with the screenshot shared above

thnx for wonderfully explaining this. Do u know some problems related to this GCD property ??

where did u get this dark theme palette ttrolka

can anyone explain the first one with an example ?

Hot_Potato This problem also has a binary search tag, how to solve it that way ?

yjgarg This problem also has a binary search tag, how to solve it that way ?

This problem also has a binary search tag, how to solve it that way ?

Can you guide me to setup these compilation flags in VS Code (minGW compiler) ??

What people fail is knowing how to prove greedy solutions but that's in my opinion the most important thing

tfg Where can we learn about ways to prove whether greedy works or not ?

can you update this beautiful list with graph problems which have been asked in 2020 and 2021 contests?

Isn't it the other way round, to reach pupil (green) you need to solve A and B very quick Whereas to reach specialist (cyan) to you also need to solve C in decent time ?

hey do you know how to use these flags in VS code is you have tried some of them ??

I thought the same way

hey just wanted to know whether problem F was a digit dp problem ??

loved the length and quality of questions picked by this youtube channel. but can this be in Hindi or English ??

Thnx a lot for responding back. I inferred two thins :- first :-

firstly, I should have generated all possible strings only once before running through each testcase (major mistake)

secondly, I will use your advice :

In problem B, can you help why I got TLE ? Here is my submission: https://codeforces.me/contest/1536/submission/118685076

My basic idea : I created three sets (names are as follows one, two, three) each storing all possible strings of length (1,2 and 3) lexicographically. Then from the given string str I generated all strings of length 1,2 and 3 and stored all of them in another set called th

Then I iterated trough all elements of set th and if any of these strings stored in th, if found in set one, two or three, I deleted that element from that set (this means that such string is already there in the given string str thus I deleted from the set which contains it besides set th)

Lastly I checked if one isn't empty, the set of strings of size 1, then print *one.begin().

Else if two isn't empty, the set of strings of size 2, then print its *two.begin().

Else print *three.begin().

In problem B, can you help why I got TLE ? Here is my submission: https://codeforces.me/contest/1536/submission/118685076

My basic idea : I created three sets (names are as follows one, two, three) each storing all possible strings of length (1,2 and 3) lexicographically. Then from the given string str I generated all strings of length 1,2 and 3 and stored all of them in another set called th

Then I iterated trough all elements of set th and if any of these strings stored in th, if found in set one, two or three, I deleted that element from that set (this means that such string is already there in the given string str thus I deleted from the set which contains it besides set th)

Lastly I checked if one isn't empty, the set of strings of size 1, then print *one.begin().

Else if two isn't empty, the set of strings of size 2, then print its *two.begin().

Else print *three.begin().

can you plz elaborate what cutoff ?? Do you mean to maintain delta rating to zero, as a pupil you need to rank at least 4000 in this contest ??

for clarification : to use this — -D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC — we have to include this in args ??

And how to use sanitizers in VS code ? ( using minGW )

how can I use these sanitizers ?? I m using windows with minGW on VS Code. I tried to compile on terminal using this command - g++ -fsanitize=address hey.cpp -o hey.exe

but then i got this error

C:/mingw-w64/i686-8.1.0-posix-dwarf-rt_v6-rev0/mingw32/bin/../lib/gcc/i686-w64-mingw32/8.1.0/../../../../i686-w64-mingw32/bin/ld.exe: cannot find -lasan
collect2.exe: error: ld returned 1 exit status

Can we use c++ sanitizers on VS code in windows machine ?? If yes, then where am I going wrong ??? anyone plz help

Can anyone help me to understand that how to use these flags on VS code (using minGW ) on windows machine. If they don't work on minGW compiler then I can try out other compilers but plz guide.

So does this all even work on VS code which uses minGW compiler ?? Can anyone guide me with setting up all this on windows ??

Lol yeah even I got the same logic like suppose n = 8 and k = 2 then a simple string can be aa+ab+ba+bb which is "aaabbabb" in any case where n is > k² we just repeat this array !!! Am I right ?

can you explain why there are collisions on using unordered_map in problem [D].If my hash-map is just used for storing frequency of every unique number in the array, then how can there be any collisions in keys ?????

okay i get this point but how could you be sure that deleting the top two elements from the multiset would fail and the other way of deleting one from the top two values in multiset would work ??

1 6 2 3 2 1 3 1 surely, our code with former logic would fail on this testcase, but pass the rest of them. What if this testcase wouldn't be there, then how would you reach to the above conclusion that the latter approach of decrementing the top two values by one would only work, and the former approach of deleting the second largest value from the top value at one go would give WA

How are you so sure ?

why aren't any difficulty level tags provided for any of the questions which falls under this contest ?