Winning Codeforces Round

1st after the end of the contest :) Hopefully I won't be hacked! Explanations video is here: • Codeforces Round #627 ...
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Website: williamlin.io/
Instagram: / tmwilliamlin168
Twitter: / tmwilliamlin168

[@ritiksingla9946]

Not only winning competition but winning our hearts by putting your time in making these live and editorial videos. Thank you so much.

[@mridulbhatt620]

I was frantically sear hing for order statistics for multiset when I realised that ai-bi might repeat. That took a hell lot of time and finally had to resort to another interpretation(was mentioned in the tutorial). Certainly learned something valueable today!!!

[@Errichto]

orz

[@tmwilliamlin168]

orz

[@mostafamarwanmostafa9975]

I swear you are like an inspiration to me

[@rafayeathossain8731]

thanks for uploading i was able to solve Upto E but missed F , now i have got hint . Thanks

[@saikat93ify]

Good Job, William. I was waiting for this video. Till what rating do you feel confident of solving a problem in a contest ? For example, I am confident of solving problems rated 1600 or 1700 in a contest. I'd like to discuss F with you. I understood that DFS1 computes the maximum subtree rooted at v for every vertex v. But, I did not understand what dfs2() does. Can you please help me ?

[@tmwilliamlin168]

dp[u] is the subgraph for the subtree of u, but we don't want to limit ourselves to the subtree of u. We also need to consider the subgraph coming from the parent of u (which is DP as well) and the weight of that subgraph is pd. This is a pretty common trick for DP on trees, when we need to calculate something for each node.

[@saikat93ify]

@@tmwilliamlin168 Thanks William. Next time, please use a more descriptive name than 'pd'. I was able to solve the problem :)

[@tmwilliamlin168]

@@saikat93ify I mean, it's a habit, just like a lot of ppl use "dp" for all values related to dp.

[@saikat93ify]

@@tmwilliamlin168 I see. It's a suggestion. William, I have another doubt. In A, I understand that it is not possible if all the integers do not have the same parity in the beginning. But, how do we prove that it is always possible if all the integers have the same parity ?

[@tmwilliamlin168]

@@saikat93ify we just look at the highest column and fill all other columns to that height.

[@shashanktiwari4442]

I did C by just counting max continuous L's + 1.. does it fail at some case?? 😛

[@tmwilliamlin168]

For contests like these, speed matters a lot, so I implement the first thing which comes to my mind. This causes me to miss simple solutions like these :P

[@sahilkalamkar5332]

Nope, it won;t fail.

[@kishanpatel3354]

First video with 0 dislike, sometimes life just surprises me!

[@laxityadav9414]

Please make a video on how you started competitive programming.

[@tmwilliamlin168]

I started with HackerRank problems.

[@tmwilliamlin168]

@Spakk 9 last year of high school

[@dashsights4258]

​@@tmwilliamlin168 and what does that mean?

[@jiakai7254]

now i will use while(n- -) rather than a for loop xD

[@JackSparr0w2023]

Thanks for the video .

[@shahriarrafsun7078]

can anyone tell me the font name?

[@elizabeth00653]

William we want more coding tutorials please!

[@fuasteriskk]

so... you dont wait for your solution to get accepted?

[@dajamesthompson]

what keyboard do you use?

[@shreyanshsingh2627]

If it doesn't hamper your performance, please consider naming variables in a more understandable way. Your code is cool, I can follow along upto like C or D (the topics I know), but it would've been much simpler with descriptive variable names.

[@tmwilliamlin168]

It actually does, a lot of CPers use one letter variable names

[@shreyanshsingh2627]

well your code is still very understandable. thanks for posting

[@abylay_gaming]

how did you get idea in E?

[@tmwilliamlin168]

By doing a lot of DP practice.

[@sharathnair1702]

whats the "%y+" thing you do after every code?

[@barun511arvindr]

Its a vim function that copies the code into his clipboard

[@souravsharma5332]

Can you suggest me a good resource to learn data structure and algorithm.. I am pretty bad at competitive programming i am barely able to solve first 2-3 question codechef long challenge..

[@tmwilliamlin168]

HackerRank was good for me as a beginner.

[@ravikothari3220]

Do a QnA

[@tmwilliamlin168]

Good idea, maybe I will make a form for it soon!

[@JackSparr0w2023]

What is the best source for learn data structure & algorithm?

[@tmwilliamlin168]

There is no best source, you have to find multiple different sources for different topics.

[@tmwilliamlin168]

@PGTECH STR3AM Google

[@brayaon]

I think you should include your GitHub account in video's description.

[@tmwilliamlin168]

You can just search up tmwilliamlin168 GitHub

[@JackSparr0w2023]

How much time do you invest on programming every day ?

[@tmwilliamlin168]

4-10 hours depending on the day.

[@simpleman9889]

.gvimrc can you share it??

[@tmwilliamlin168]

pastebin.com/qMvFYGqb

[@dngiang2003]

tôi vẫn còn vật lộn với pascal 🤭

[@rajdeepsahaofficial]

Are you human?😅

[@tmwilliamlin168]

Yea I sometimes doubt that. I'm too stupid in life to be human.

[@rajdeepsahaofficial]

@@tmwilliamlin168 🤣

[@prarinamderia309]

Can you gave me a idea of a tree related qns??

[@tmwilliamlin168]

What do you mean?

[@prarinamderia309]

@@tmwilliamlin168 don't misunderstood me sir ,i mean can you explain dp on trees and solve example with more clarity....

[@tmwilliamlin168]

@@prarinamderia309 it's hard given the time that I have. I think that there are good resources for DP on tree out there already.

[@prarinamderia309]

@@tmwilliamlin168 actually in tube there no good available resources so I told you ..... Ok ,don't mind sir.

[@prarinamderia309]

Sir , you have your instragram account ?? Bcoz i have one tree related question ,can you solve this question piz...., Send me your instragram account link

[@huabiao7521]

What is your age?

[@tmwilliamlin168]

17

[@kartikbhanderi9210]

@@tmwilliamlin168 are you kidding me!

[@tmwilliamlin168]

@Spakk 9 I have done a lot to reach this level. 9 years of programming, 4 years of math contests, and endless practice have gotten me to my level today.

[@harshitsinghvi6158]

@@tmwilliamlin168 this reply has come straight from the heart ...flashing through all the days of hardwork !!! keep it up mate...!!!

[@harshitsinghvi6158]

Btw. what keyboard do u use.... i am planning to buy one ...any suggestions

[@prarinamderia309]

So I send you this qns

[@mridulbhatt620]

I was frantically sear hing for order statistics for multiset when I realised that ai-bi might repeat. That took a hell lot of time and finally had to resort to another interpretation(was mentioned in the tutorial). Certainly learned something valueable today!!!

[@rupanshuyadav4483]

what keyboard do you use?

[@tmwilliamlin168]

I don't know, I just bought a mechanical keyboard randomly.

[@rupanshuyadav4483]

@@tmwilliamlin168 It sounds good