Codeforces Round 961 (Div 2) - Official Solution Discussion

[@shahainmanujith2109]

Problem C was insane! Thank you for making it easy!

[@CPwithShayan]

Most welcome

[@ShubhamKumar-k6q]

Damnnn great content, best guys for post contest tutorials!! btw you like a kashmiri indian.

[@CPwithShayan]

Lol Thank you!

[@DonavernAng]

Loved the content, subbed

[@CPwithShayan]

Thanks man!

[@tusharsingh9346]

thank you for the editorial !

[@CPwithShayan]

Most welcome!

[@NG-ot4nb]

Hi Shayan Love your editorials, keep up the great content. Actually I asked this question in stream too when you were solving a question I was able to get some advice from the viewers but I wanted to get your advice too. I am a Max Specialist, I generally have a performance rating of 1600-1700 in Div3, Educational and Div4's but in Normal Div 2 rounds I always seem to struggle. I dont know what happens. In almost all educational I am able to solve 3 questions in about 50 mins or 1 hour but in normal Div 2 rounds I am generally able to solve just 2 or If i do 3 I am not able to do them fast enough. And in the worst case sometimes just 1(like today). And since most of the contests are Div2 my ratings takes quite a bit of a hit because of this. And I dont want to skip the Div 2's since eventually I am going to have to perform well in them to grow beyond a certain level. Any Advice on how I can improve here?

[@rlm3227]

I am also going through this stage : (. Hopefully I'll become CM within a year with a lot of practice

[@CPwithShayan]

Hi, Thank you! I will definitely cover it in the upcoming livestreams. I will have some dedicated livestreams for discussing such things.

[@Jazzimus]

great explanation!

[@CPwithShayan]

Glad you liked it

[@aryanagrawal9103]

thanks a lot! also, would be even better if u take some test cases as examples for explanation

[@CPwithShayan]

Sure. Will do in the next ones

[@Harsh-w1i]

Loved the explanation, great going Shayan. Btw you look Indian but your accent is of the states. 👏👏

[@CPwithShayan]

Do I really? Lol Never noticed it

[@sujalsuri1109]

Thanks for the video editorial

[@CPwithShayan]

Thank you for the support!

[@jugnugupta6839]

Awesome explanations 🎉

[@CPwithShayan]

Glad you liked it

[@saeedjalali7339]

I've been laughing for 5 minutes straight when Shayan started with "Salam guys how are you doing" said hello in Farsi unintentionally and didn't notice.😂

[@CPwithShayan]

😂😂 I tried to act like nothing special has happened

[@tylerd5924]

Everyone knows that much nothing awkward ig 😂

[@khinljk]

I also thought does Shayan know 'Amharic' since 'Salam' means hello, hi ... in 'amharic'.

[@Dontpushyour_luck]

So, the inference I got from problem C is this : if a^(2) > b^(1) and a b^(2x) and a^(2x)

[@Mohammad-w5l5j]

Hi Shayan, thanks for your efforts to make a good editorial. I think problem B1's solution has a ' out of bound' risk because there is no bound checking for j and L or I'm making a mistake?

[@italk-gj5kk]

thanks

[@CPwithShayan]

Welcome

[@vudo1013]

hello in problem B2: 1

[@harshbam603]

Can you explain that why are we doing last-=c1 ? here c1 will denote the number of times we can perform the ops on v1 such that it still remains less that v2. but i dont understand why do we need to subtract it.

[@harshbam603]

update : undetstood the reason it is because if we perform the last number of steps on v2 it will be lot bigger than v1 , since we need the minimum number of steps we remove the number of steps for which v1 < v2 ensuring , to ensure after performing the steps v2 gets to a minimum value that is greater than v1.

[@harshbam603]

also i hope to be as good as you one day :)

[@grandhisrinikhil6259]

Hello In problem B1, I have the similar approach but I used unordered_map to store the count, it is giving wrong answer in pretest7, how to debug the error as the testcases are not shown?

[@divyanshushekharjha4639]

Take Long long

[@sahej1766]

In problem A, why can't we start filling from the first cell that is (1,1)? will we consider it as a diagonal also? why do we start filling from the middle one?

[@munvut877]

to get max diagonals start from small to big , in this prob minimum was asked so go from big to small

[@sahej1766]

@@munvut877 thank you🙏

[@mosalah151]

Love your editorial really .. Go a head !! .. But Why dont you sometimes invite tourist 😅

[@CPwithShayan]

Lol, someday hopefully

[@youtubeunbanmepls]

thank you

[@CPwithShayan]

You're welcome

[@darpanlunagariya9021]

If it possible, you should turn off background possible, it is very distracting!

[@darpanlunagariya9021]

background animation*

[@CPwithShayan]

I see. I will put a vote in the Telegram channel about it to ask what to do. Thanks for mentioning.

[@sahajgupta5364]

For problem B2, what if i greedily buy flowers of type (i + 1) and then buy flowers of type (i) from the remaining. I was using this configuration and then trying to adjust the current solution to the optimal solution but was not able to do it. Can someone help ?

[@jiakai7254]

you need to buy more than 1 type(i) flower for every type(i+1) flower u sell in order to improve the answer (using while loop). Cos if you sell 1 type(i+1) and buy 1 type(i) your answer gets worse by 1.

[@tylerd5924]

Take the case where petals, quantity={(7,2),(6,3)} and maxmoney=18 or 13 here we have to use sliding window technique. Which worked with few minor adjustments for B1 but for B2 this will result in TLE for sure, so I gave up this approach 😂

[@tylerd5924]

But I think we can do it that way also we can make some changes in shayan's code

[@prakhargupta1688]

32:15 won't b always be zero?

[@CPwithShayan]

Hi, There will be some money left after the first step (because we can pick limited numbers of flower type 1, at most p[i].second) So, we greedily have to pick as many flower type i + 1 as possible and it won't be necessarily 0.

[@prakhargupta1688]

@@CPwithShayan oh yeah, completely forgot there were constraint on number too

[@mezenabyd]

Hey Shayan, I really want to know why my code doesn’t work in problem B1. It seems exactly like your solution. I sent you my solution on LinkedIn.

[@CPwithShayan]

Hi, Have you checked the test case that you got a WA on?

[@mezenabyd]

@@CPwithShayan WA on test 23