Codeforces Round

The first Division 4 round on Codeforces! Ended up 4th, since it was a Divison 4 contest.
codeforces.com/contest/1352/s...
Second channel (William Lin ++): / @williamlinpp4187
Website: williamlin.io/
Instagram: / tmwilliamlin168
Twitter: / tmwilliamlin168
Discord: williamlin.io/discord

[@othmanebentaleb]

For the last problem, there is a permutation that is always valid: print odd numbers in a descendant order, then print the even numbers in ascendant order (swap 2 and 4 to match the diff condition)

[@yesil1026]

Yes, that is the first thing I also considered. For odd n: 1, 3, 5, 7, ..., n, n - 3, n - 1, n - 5, n - 7, n - 9 ... is a valid sequence. For even n: 1, 3, 5, 7, ..., n-1, n - 4, n, n - 2, n - 6, n - 8, n - 10 .... is a valid sequence.

[@bsethupathi1]

This is a Div 4 contest targeting the unrated coders. He is too OP for this round.

[@huskydj1]

He was participating unofficially...

[@ATGG]

Literally, every time I see your videos, my mouth stays Wide Open

[@1010ansh]

Thank you for providing such a good explanation and implementation for this problem.

[@ultra_mega_tronic_source]

I don't know what's happening...

[@cartist3019]

You're ultra Pro in competitive programming William

[@parthshah8057]

Ended up 4th, since it was a Divison 4 contest. Will end up 3rd, since it will be a Divison 3 contest. Will end up 2nd, since it will be a Divison 2 contest. Will end up 1st, since it will be a Divison 1 contest.

[@clipit4503]

😂😂😱

[@User-ip9dg]

Being number 1 is tough when tourist is in a contest.

[@abuhuraira071]

@@User-ip9dg MifafaOvo also

[@shashanksabharwal8591]

*hey* may be *you* guys are good coders ... Please help me guys .. I have only 1 year to learn programiing and build some good skills so i will get a good job... I am learning C language still please reply anyone.. What to do after C .. For getting place ld in companies like amazon, paytm

[@sauravkarmakar3704]

@@shashanksabharwal8591 language doesnt matter , the algorithms u learn and their implementations matter

[@utsavsingh899]

As always the timing is awesome... just after contest (perfect time to upsolve)

[@shashanksabharwal8591]

Rohit Pal hey may be you guys are good coders ... Please help me guys .. I have only 1 year to learn programiing and build some good skills so i will get a good job... I am learning C language still please reply anyone.. What to do after C .. For getting place ld in companies like amazon, paytm

[@dudemysterio]

Great Vids but William could you make a video with your VIM setup it would be a great video for people. Keep up the good work.

[@almaaune3596]

Hi William! I really enjoy your videos! Could you perhaps do another post on how you improve your programming skills. I would like to get better with coding logic but I am hitting some walls, for example coding logic of hackerrank's easy to medium section. Is there reference material that you read to get better?

[@justaguyonyt869]

He’s Asian

[@rohitpal7739]

I did 4 took me 2 hrs almost did 5 and was happy until... Lot to learn

[@clipit4503]

You can do it! You will get there practice makes better!

[@ritamr2690]

i didn't get any... i started on c bc it looked so easy but i got tle and then just rage quit lol

[@rohitpal7739]

@@ritamr2690 keep trying and be consistent that's what I am trying currently

[@rohitpal7739]

@@clipit4503 Thanks

[@shashanksabharwal8591]

@@rohitpal7739 hey may be you guys are good coders ... Please help me guys .. I have only 1 year to learn programiing and build some good skills so i will get a good job... I am learning C language still please reply anyone.. What to do after C .. For getting place ld in companies like amazon, paytm

[@sterlingmaloryarcher747]

Lin: Makes video so that people learn about CP Me: What are your VIM settings?

[@ianpan0102]

syntax on set nu set ai ... Pretty much it

[@user-lq9jz3hk5i]

Can you please make a video on how to setup Vim. I watched your CP video and it has inspired me to code too. 😊🙏

[@JayPatel-jn7cu]

3rd problem can be seen as - ans = ans/n + k , find the ans ans =floor(( n*k -1)/(n-1))

[@tanmaymishra9203]

Lol..I found formula (k-1)//(n-1) + k.. dunno how it arrived

[@jayantjha3128]

Thats wrong actually. Try n=7 and k=97. Answer shld be 113

[@jayantjha3128]

I also thought of the same

[@yesil1026]

K'th not divisible by n can be calculated analytically. Its k + floor((k - 1)/(n-1))

[@EintsWaveX]

Omg dude, i never think such of this solution... Impressive

[@boomboom-9451]

why k-1 part

[@getsuha]

Hi @William Lin Can you please share a video with your VIM settings....

[@The_Wyverna2929]

What is this font in Vim?

[@0xero7]

I found another elegant(imo) solution for G, first it is obvious for n < 4 it's impossible for n = 4 you can have 3 1 4 2 now, for every increasing n, add odd numbers to the left and even numbers to the right. for example if n = 7, add 7 and 5 to the left of 3 1 4 2, and 6 to the right. 7 5 3 1 4 2 6 and so on :)

[@srinivast84]

Cool

[@anoubhav]

Really cool

[@debadiptobiswas5611]

i did the same

[@youarecorrectiamwrongbecau1338]

Oh it's amazing.

[@thallium54]

same solution

[@tilakmadichettitheappdeveloper]

i can imagine 4 years from now div 1 in 20 minutes.

[@yz767]

Good job and thanks for explanations :D

[@aw12sdfx]

my new favourite asmr

[@sriharshaananthoju8671]

Will rating changes be so minimal in this division because only greens and greys

[@rajdave9862]

Hey, I literally took 4 minutes to understand 2'nd problem (B) but you solved it in less than 3 minutes How how how? Please tell us How are you able to think this much faster, Do you have old experience of these problems or you came across these problems first time

[@rajdave9862]

@@sasmitvaidya3594 that's sounds great, thanks Sasmit Vaidya

[@karanpatel7974]

Great video William, do you have any advice to learn c++ as a beginner, I know java (programming) but I am trying to learn c++, any advice would be really helpful.

[@youarecorrectiamwrongbecau1338]

I was really scared from c++. Just couldn't switch from python. Now I find cpp better in many situations. I would give you an honest advice. Mostly people will say read this read that. I'll say, just learn 3 - 4 important operations of all stl data structures by googling their name like map set vector etc. Almost everything in cp is done using those 90% of the time.

[@gameplayvideos3113]

C++ is way easier than Java and python is the easiest

[@rashidmazhar023]

How do you have this themed chrome?

[@Zildras]

what keyboard uses in this video?

[@entertainshala]

How did you learn all these

[@kuljeetsinghvirk1299]

love your content man. keep it up..

[@kuljeetsinghvirk1299]

I was also thinking to participate in this contest but I think I did right by not participating

[@sauravkarmakar3704]

@@kuljeetsinghvirk1299 why

[@kuljeetsinghvirk1299]

@@sauravkarmakar3704 kidding bruh!!! I was just admiring his skills.

[@JoaoVictor-lq5ew]

Awesome, I like so much your videos, thanks for all

[@forhanshahriarfahim9493]

@William Lin How you load all problem in one page ??

[@mostafamohamed2]

When you open normal problems page you can see "Complete Problemset" just click it.

[@teddychow8487]

When collab with tzuyu_chou?

[@aliabbasattarwala9130]

Which editor u use ?

[@srinivast84]

It's Vim (Visual IMproved).

[@HarshSharma-je8rk]

Is there any discord server created by William lin... Pls send the link

[@bensontoh92]

check the description....

[@shashanksabharwal8591]

hey may be you guys are good coders ... Please help me guys .. I have only 1 year to learn programiing and build some good skills so i will get a good job... I am learning C language still please reply anyone.. What to do after C .. For getting place ld in companies like amazon, paytm

[@aser2535]

Did you do math competitions before competitive programming? Also, do you know discrete math? If so, would you say that discrete math has helped you, whether directly or indirectly in solving these questions?

[@itsvaleska7814]

Aser just incase he reply

[@badeeesmandar2552]

1st problem took me an hour😂😂 I'm soo noob😭

[@jethalalnhk2409]

I could not solve second

[@AdityaSharma-ei4gq]

You guys are solving problem?

[@Sam-nd6np]

I still don’t understand how he did problem 1 so quickly, can anyone explain how? I did it in 16 minutes lol

[@18PregnantAndProud]

Sam Penny maybe he did that same problem before

[@rocknroll7967]

He is red bro, they can generally solve these type of questions without even picking pen and paper.

[@mynewnameisbeautiful___4717]

Its very easy if you are familiar with problems when you need to do somthing with the digits of a number, I solved it in the contest ~1.5 minute

[@shashanksabharwal8591]

Rohit Pal hey may be you guys are good coders ... Please help me guys .. I have only 1 year to learn programiing and build some good skills so i will get a good job... I am learning C language still please reply anyone.. What to do after C .. For getting place ld in companies like amazon, paytm

[@sauravkarmakar3704]

@@shashanksabharwal8591 some OOP language, then focus on algorithms and solve interview questions

[@aryamitabh]

For G, you can just go 2 4 6 8 ... then go back in reverse for the odds but by changing a couple of things. Like for n = 10, you can do 2 4 6 8 10 7 9 5 3 1. Just a change in the order of 7 and 9. Another method can be placing the elements in 4 groups based on their value mod 4. Then printing all 0 mod 4 in ascending order, then 1 mod 4 in descending order, then 2 mod 4 in ascending and 3 mod 4 in descending.

[@tanujnamdeo]

Why does he use comma with cin? Can anybody explain?

[@ManishKumar-jj1nt]

If your talking about cin.tie? If yes then it is used for fast I/O in c++. Just google about them to know more or ping me.

[@happyhappyguy5034]

@@ManishKumar-jj1nt No

[@happyhappyguy5034]

Comma is just for separating statements

[@happyhappyguy5034]

And also with comma, you do not have to add the curly braces to contain two statements

[@tanujnamdeo]

@@happyhappyguy5034 Thanks

[@goldy7243]

Superhuman speed

[@mynewnameisbeautiful___4717]

I think this round was has the worst problms for beginers

[@sauravkarmakar3704]

yes i completely demotivated me

[@happyhappyguy5034]

why？

[@tanmaymishra9203]

Do u mean the problems were more easy or more difficult?

[@priyanksatasiya1366]

best part is 28:25 is there anything else? okay ya nothing else😂

[@almuhimen8023]

For problem C I was sure I will get a TLE. That's why ai tried figuring out a formula. So, my time complexity was O(1).

[@andrewalbrekht9399]

which formula you used? I also got a TLE , but i couldnt firuge out a formula

[@ritamr2690]

@@andrewalbrekht9399 me too i basically did brute force

[@debadiptobiswas5611]

For C: answer is ceil(n*k/(n-1)) - 1

[@kaiovieira230]

Simpler than mine =D

[@CharlesMacKay88]

ceil(n*k/(n-1)) - 1. good find.

[@debadiptobiswas5611]

@@CharlesMacKay88 Yeah there's a -1, thanks for pointing out

[@karthiksk7246]

I did the same!!

[@abhiraj9990]

4 or 5th Ps:i know ur alts 😂😂😂

[@vamsikrishnavalluru611]

Damn the screenshot is good but why do we need the head on the top corner :/

[@kaiovieira230]

In C, here is my method, which I'm proud of: The answer is ((N - 1) / K)*K + (N - 1)*K ( - 1 if (N - 1) % K == 0) Don't ask me why. I hope that intuition method is hack-immune (correct)

[@pguerin7095]

I'll never understand how people just come out with formulas like that during contests lol

[@snehasishsamanta1319]

I also applied the same formula

[@SamDaBest]

I used the same formula, it won’t be incorrect because it is calculated with math

[@daviddafitt]

O(1) solutions ftw XD

[@mashedpotato5694]

I did n*k/(n-1) and -1 if k%n=0

[@longlin18]

I don't understand problem B! Why the output of 100 4 is YES 55 5 5 35 different his result YES 1 1 1 97 but he right?

[@zarc5744]

Output For each test case print: YES and the required values ai, *if the answer exists (if there are several answers, print any of them)* For such type of questions its better to not look at the testcases, come up with your own approach that satisfies the question. The testcases are designed in a way to trick you, so you start spending time on how to get output like the test cases and eventually you don't solve the problem

[@abdoulayebah215]

Hello everyone! Can you tell me please which language is he using ?

[@srinivast84]

It's c++.

[@kairatopa9564]

Z++

[@gameplayvideos3113]

10++

[@roloskan9671]

c:

[@pavanvenkat9182]

Missed your videos

[@vinaysinghjadon1959]

This guy is hacking !!!!!

[@shashanksabharwal8591]

hey may be you guys are good coders ... Please help me guys .. I have only 1 year to learn programiing and build some good skills so i will get a good job... I am learning C language still please reply anyone.. What to do after C .. For getting place ld in companies like amazon, paytm

[@pk4780]

you should stream on twitch

[@khaledjubeh8818]

screencast for the next Div1 round.. its will be more interesting

[@SamDaBest]

I only did 4 problems :( I’m so bad

[@ezalor9555]

Well I did 0 so you're better than me, cheer up!

[@andrewalbrekht9399]

i did only 1 problem :(

[@pluviophile762]

I also did only one

[@teji7723]

No dislikes :D

[@jewishfloppa6969]

He types too fast X_X

[@HarshitSharma-cl6io]

I am in love with your skills I want the same skills pursuing cse

[@gameplayvideos3113]

Since you don't even know the spelling of pursuing/pursue I doubt you will make it that far

[@gameplayvideos3113]

@Samuel Benson 😂😂😂

[@HarshitSharma-cl6io]

@@gameplayvideos3113 have u ever hear abt typos ....or rather say typing errors nevertheless u will say u don't even know the spelling ........lol ...i don't mind u corrected my mistake, in fact, I will prove u wrong by practising and grooming my skills ...have a great life ahead

[@gameplayvideos3113]

@@HarshitSharma-cl6io if you need any help regarding coding/programming reach out to me. I am a developer at IBM

[@aishikbhattacharya7823]

This is...

[@nishansingh77]

This guy is too too fast! He is the flash of CP!

[@teddy911]

你中文好不好啊，下回视频说说中文呀

[@Deepakverma-ox8pd]

This is wrong why u participated its for under rating 1400 ....this is why beginners cant get good rank.....😅😂😂😂😂 I did 3.....😅

[@a.sana04]

I did 0! 😂

[@cheissmart]

@@a.sana04 0! = 1 XD

[@anmolvarshney5-yeariddindu442]

he participated unofficially(doesn't affect rank)😂😂

[@TahsinAhmed-yj9ns]

Did A&C stuck on B Any help on B? When should we print no

[@ankitthapa9062]

@@TahsinAhmed-yj9ns read the ques carefully.