Alex7's blog

New RAD youtube channel with tutorials and stuff.
By Alex7, history, 9 years ago, In English

So I just made my first video which is a step by step tutorial of this problem 634E - Preorder Test. The video link is Here. Please watch it and tell whether I should make more or improve anything. Your suggestions are welcome :D.

(P.S. Sorry for the terrible quality, somehow youtube converted my 720p to 360p for no reason. I'll try to fix it.)

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9 years ago, # |
  Vote: I like it +16 Vote: I do not like it

It's a cool idea, but I don't completely agree with your problem choice. I think that problems in the range div1 B-C will have a much larger audience. Maybe you should setup a polling system or something?

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9 years ago, # |
  Vote: I like it +8 Vote: I do not like it

I really like where you are going with this. It would be nice if we could see some DIV2 problems aswell.(B-D) Cheers

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9 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Oh I'm glad I'm getting feedback. I certainly plan to do a wider variety of problems in the future. I just wanted to start with this one for the reasons I explained in the video :D

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9 years ago, # |
  Vote: I like it +19 Vote: I do not like it

Learning from a video is a very nice way to learn. You show us how you reach the solution and that is something you don't find too often, even when you read the editorials of the problems. So congratulations and thank you very much!.

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9 years ago, # |
← Rev. 2   Vote: I like it +6 Vote: I do not like it

rad channel man

you got yourself a subscriber

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9 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Dope channel, I love how you explain your thought process instead of just going over the solution so it will be more helpful for solving different problems in the future. Thanks a lot Alex.

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    9 years ago, # ^ |
    ← Rev. 2   Vote: I like it +5 Vote: I do not like it

    I misread the comment initially, please ignore this sorry :D

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9 years ago, # |
  Vote: I like it +7 Vote: I do not like it

you should record the thought process of all the problems of a particular contest after the contest is over and release it just like editorials, especially div2 C, D, E.

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    9 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Well it's a good idea, but that's too much work. For now, I think I'll do one video a week.

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9 years ago, # |
  Vote: I like it 0 Vote: I do not like it

I'm also open to requests, if you have a some particular problem you'd like me to do. I already got a few so it's only fair I tell you guys that I'm open to that.

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    9 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    I was not able to solve it even after going through the tutorial(Problem Statement)

    Thanks in advance :)

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      9 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I've added it to my TODO list, I have a couple of requests before than one though. I'll message you when it's ready.

      Thank you for your suggestion :D

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9 years ago, # |
  Vote: I like it +10 Vote: I do not like it

The reason for the WA is that is possible that the root node and its children are deleted and that the second dfs then never visits the part of the tree that isn't deleted. Small challenge case: '7 5 2 2 2 2 2 1 1 1 2 2 3 3 4 4 5 4 6 5 7' (answer is 2, but first attempt returns 1).

Btw I liked the idea and the video. You solved the problem in a somewhat different manner than I did. For me personally the explanation+coding could have been a lot shorter, but then again, I realize that this may not be true for the target audience.

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    9 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Yeah I realized it instantly but didn't quite explain.

    Well you're not the first one to say that it was long. After carefully analysing it I could've cut down around 10 mins without sacrificing clarity.

    I wanted to be on the safe side, having higher rated people say it's too long is better than having people say "it was too short and unclear".

    I certainly appreciate your feedback, and will try to balance it out in the upcoming videos :D

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