Codeforces Round

[@pangeranbottor]

this is the editorial we all need after every codeforces contest. salute!

[@adityakrishna11]

I have been following you for like 2 weeks now and I'm also on your discord channel. Can't thank you guys enough for the effort y'all put in!

[@utsavsingh899]

I love his speed.. as soon as the contest ends, explanations are out!! Thanks for the awesome content!!

[@SlamMur]

Writing explanations during ongoing contest - next level ;)

[@NotFound-hy7qb]

That is just unbelievable

[@markcagas1622]

In problem B, repeating the first b letters of the alphabet until the length of the string is n works as well. 7 5 3 abcabca 11 7 4 abcdabcdabc

[@rishijha9860]

I applied same approach

[@jashanbansal2613]

Metoo

[@surajpatel-bk1ip]

me three

[@orthocresol4284]

yup no need to consider a

[@adityakrishna11]

Yep same the value of a makes no difference here!

[@mohamedelkaramany9863]

My first contest to solve 4 problems. You're a genius.

[@adityakrishna11]

Yea I felt so elated! I know the questions were easy but baby steps am i right?

[@tawseeftaher9109]

@elkaramany what's your cf id,brother?

[@varunrajesh1715]

The second i saw you came 26th I waited for this :)) Thanks for the quick posts!

[@parvgour5284]

who is the first...?

[@varunrajesh1715]

@@parvgour5284 tourist codeforces.com/contest/1335/standings

[@jawprince7720]

That problem D solution was the single biggest brain thing that I've ever seen, I'm quite literally shaking, both from awe and anger that my answer was so unnecessarily complicated

[@dhananjaysonawane1996]

If such a video comes after each codeforces round, I am going to click on a bell icon! As usual, a great explanation!! Thanks buddy :):)

[@mohamedelkaramany9863]

For D I considered the following (i,j) (0,0) (1,3) (2,6) (3,1) (4,4) (5,7) (6,2) (7,5) (8,8) then if (sudoko[i][j]==1)sudoko[i][j] = 2; else sudoko[i][j] = 1; and printed the sudoko array

[@casimirronnlof7396]

Bruh my solution on D was so much more complex than yours, to think that I could have done it by only changing e.g. the 2's to 1 ARGH it hurts my brain that I didn't think of that. Luckily I still got it right. Awesome video anyways, keep making them!

[@atanusaha143]

For problem D: A single change in a row will satisfy all the 3 conditions. A single change means picking a value and changing it with between 1 to 9 except the picked value.

[@shivaramprasadmeesa7189]

In Problem E as you are keeping nested for loop which has 40000 iterarions and t is till 10^4 so overall it is 4* 10^8 which should give TLE

[@TheNayanava]

Thank you so much brother for putting up this content! Please keep doing it!! You know me from Discord btw.. :P :P. Thanks a lot for this!!!

[@shivaraj-bh]

A little bit more advanced version of first problem can be framed as ,given n candies, distribute them among k students such that a1>a2>...>ak and n=a1+a2+a3... ak. This came through my mind because, initially I didn't see the fact that there are only 2 sisters. So I thought combinations with repetions can be used here, because you have n candies and you have some poles (sisters) that will separate those candies between sisters, number of ways to do that will (n+k-1) choose (k-1) where n is the candies and k is the number of students (here two sisters). Because of the fact it is 2, the equation becomes, (n) choose (1) which is n. But to handle the fact that a>b, we have to give the first half initially to a and distribute the rest. So a always gets n/2+1 candies and remaining is distributed. So after that I realized this can be extended to more interesting version, as stated above and could be B or C problem in div3

[@prateeksinghal630]

Thanks for returning to the normal routine ♥️♥️

[@samprasdsouza6993]

Approach for anti- suduko is legendary

[@HarmoniusE]

I mean I spend 1.5 hours to understand 2 and got an error, but u solved it in one sec XD

[@parvgour5284]

this is because we have the experience of only 10 months to 1 year and he has an experience of more than 5 years...

[@93hothead]

He probably didnt solve in 1 sec depending on the score he got in competition

[@Amrable]

Simple approaches, love this !

[@kabboghosh1853]

i m just fan of u,editorial all we need

[@FPLogistic]

Instead of doing (n-1)/2, I was doing (n/2)-1... It wasn't working for so long until I did some random stuff and made it work out somehow

[@ehrazakhtar8336]

The Explanations are quite great but really missing the face cam during the actual submission during contests.

[@vladandenda9462]

William can you do video about your vim setup ?

[@subhambanerjee6334]

I solved the frst 3 problem but not able to solve last 4 thanks it helped a lot be sure to make after all contests

[@saifu07]

Ohh man, Dth one is simplest but I failed to think this and got WA, I am dying now

[@NotFound-hy7qb]

Great Work You just make solutions look so easy👍

[@surajpatel-bk1ip]

I just love your codeforces editorials. for problem c : can we directly do this : say x = max. freq of an element in array y = unique elements in array - 1 (remove this guy x ) if( x == y) result -> x if( y > x ) result -> x if( x > y) result is min(x - 1, y + 1) ??

[@cripz4203]

I did the same thing

[@jonty3551]

I was about to comment the same thing.....yea...i think its fine too as far as i can see

[@jonty3551]

I think we can go like this too: If x == y, cout x -1 If y > x+1 cout x +1 Else cout min of x, y

[@surajpatel-bk1ip]

yeah man, same thing, i guess its just my y is 1 less than yours so those three conditions simulates same as two of yours

[@jonty3551]

@@surajpatel-bk1ip oo....i got accepted after submitting btw.....👍

[@dhivagarm6497]

Simple and clear explanation thanks :)

[@manjunathvasam4981]

That helped a lot, thanks!

[@MenelaosKotsollaris34]

Thank you for the video William! What hardware & sofware are you using for your drawings?

[@Shun8881]

thank you so much for this!

[@christianoronaldo1662]

i liked your effort

[@shuxianlai3637]

Hi there thanks a lot for your wellmade vid. I am a newbie in cp and this div3 was my first comp and i dont have anyone to discuss my code about and i couldnt check what went wrong with my logic for the contests because they dont show the test cases output. I was thinking if you have any suggestions for my situation, like is there any forum out there for peer reviewing and casual discussion?

[@shuxianlai3637]

Lmao the seen

[@alexwexov4298]

Liked that you use vim.

[@camper8650]

hey , in problem E2 will the O(n*(max(array)) will work ? and what's your time complexity ?

[@eternalgreed6715]

Can you make video how to set up compiler , gvim and etc for competitive programming, please? I think it will useful not only for me. Thanks!

[@rkhamim4574]

Nice editorial

[@yurashymon]

I want to see how you write cf and after explanations/ make next time "cf winning" it is very interesting to see how somebody write cf

[@Satyam22jul]

Thanks brother please also upload the div 3 that will going to happen on 21th april😍😍😍😘😘😘

[@Satyam22jul]

We only want explanation by you how you attempted that question🙏🏻😅😅

[@hackerhaddi]

Please consider adding timestamps for problems.

[@adarshtadwai5293]

I got TLE for E2, if I didn't write - if(occ[a].size() == 1) continue; So is this the efficient solution or are testcases week?? I am unable to write anything on your discord so I wrote here.

[@rhac79]

Thank you very much

[@lucygaming9726]

Whats the name of the drawing board software?

[@ritikagupta8847]

If in dfs1 first two nodes are in the cycle then dfs1 will not set visited1 other nodes connected to this component and when they will be again in dfs1 it will be considered as a cycle which is wrong. Am I wrong somewhere? Please correct me if so

[@pqazx1]

Plz give soln of education round 85 as well of codeforces

[@felipealferez4461]

in problem D a valid answer could be to change only the main diagonal by '1' and if there is already a '1' in that position, then a '2' would be placed, right? Since we changed at least 9 numbers and changing the diagonal would make the entire sudoku change and be wrong. I tried to do it that way but I got WA in the first test. Why do I get a WA if I am already fulfilling the conditions?

[@markcagas1622]

You also have to check each 3x3 block

[@varunrajesh1715]

You need to change a number in each box too

[@pradiptarakshit7751]

Diagonals doesn't cover all 3×3 sub matrices

[@kurtis5073]

剛考完就有解釋可以看😂

[@Rotengon33]

Can you do your environment setup?

[@showmickkar7793]

Hello. I am a very beginner. I could only solve 2 problems in contest time. And in almost every contest I can solve 1 or 2 problems. What approach should I take to improve from there?

[@younlok1081]

practice makes perfect

[@rishabhjain2084]

if you can solve A&B practice D. If you can solve A, B, C practice E.

[@souravprasaddas5909]

Please make on codeforces rating system

[@sandipanhaldar61]

why is it necessary to push n at the end of each occ vector in E?

[@johnstonliu]

What gvim theme are you using?

[@dutchboybmx]

Sick

[@teji7723]

What IDE do you use?

[@deveshjha5141]

Which digital pen do you use in onenote

[@vaibhavsingh4108]

which editor do you use..

[@ankitjoshi6066]

if(c[u[0]][u[1]]&1^1) ++a[d%cyc.size()]; how this worked in problem F c[u[0]][u[1]] this will give char value shouldn't it should be converted to int

[@apoorvamittal4112]

why did you reverse the edges?

[@adityamishra4458]

dude u did not doo codechef long challenge ..

[@Satyam22jul]

Bro you have some problem in clarifying qs c

[@ritikagupta8847]

Can you provide link to your code??

[@sickman577]

please let me know the name of the font

[@93hothead]

Is this in cpp?

[@rkhamim4574]

Can i have this code

[@mahinhossen6100]

My 2hr is equal to ur 8min

[@xcg1234]

牛逼！

[@armanyamaheshwari9967]

First

[@II_xD_II]

NO one cares -___-

[@younlok1081]

@@II_xD_II +111111

[@parvgour5284]

who got the first rank...?

[@II_xD_II]

@@parvgour5284 wdum?

[@parvgour5284]

​@@II_xD_II i am only asking that who ranked one in the contest...

[@vickySekaran]

do you stick your mic inside your mouth whats that wierd sounds you make?