RockyB's blog

By RockyB, 4 years ago, In English

Hey yo everyone!

Noticed that no one discusses LeetCode contests here, so let's get started.

So today I recorded a screencast + commentary. I hope you will like it, enjoy watching :)

https://youtu.be/cjyZyVWWYgQ (ranked 9th)

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By RockyB, 4 years ago, In English

Hi everyone :)

You could notice that last time I trying hard to make content on my youtube channel better. If you don't know anything about my channel, I do video analysis of nice educational Competitive Programming problems, observe cool algorithms, do screencasts, also I plan to add coding interview problems content.

I truly believe that potentially I can help many people as well as myself to achieve not only professional goals but also become much better in CP.

So, today I recorded an interesting and in some moments funny screencast with cool detailed timestamps.

0:00 - Starting
0:30 - Solving problem A
3:30 - Solving problem B
6:16 - Solving problem C
10:05 - Solving problem D
14:27 - Solving problem E1
28:23 - Thinking on problem E2
41:16 - Switched to problem F
1:10:34 - Solving problem E2
1:36:37 - Debugging problem E2
1:40:00 - Finishing debugging and finally submitting E2
1:41:00 - Thinking on the last problem F

I hope you would enjoy the video. If you have any feedback/suggestions, you're welcome. Also, don't forget to subscribe to the channel, by subscribing you motivate me to work hard and make more cool content :)

Link to the screencast: https://youtu.be/afn_V7YkX3U

UPD:

Finally all solutions passed a system testing, ranked 50th among 18k+ participants

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By RockyB, 4 years ago, In English

Hi everyone!

Am I only one having troubles with the leetcode contest, it seems that leetcode doesn't work right now.

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By RockyB, 4 years ago, In English

Hi everyone :)

Yesterday my friend bekzhan29 and I were brainstorming on problem G from recent educational round, in order to upsolve it. I found this problem very cool and thus today I made a video solution for that problem.

I was taking, sometimes retaking, editing, improving sound quality in that video for almost 5 hours. So make sure to subscribe to the channel and like the video :P

I hope that this video somehow will help you to improve and maybe finally achieve your CP goals.

Link to the video: https://youtu.be/Nuym8ejFH_w

UPD: Timestamps were added, so now it's more convenient to browse through the video.

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By RockyB, history, 4 years ago, In English

Hi guys :)

Some of you might know that I have YouTube channel where I do screencasts, explain algorithms and observe interesting problems.

Since we all love cool problems and want to improve in competitive programming I want to start doing videos more recently. So, If you have any interesting, educative problems of different levels, please share them with me in the comments below. I will try to select fabulous ones and make video solutions.

For example today during AtCoder Beginner Contest I found problem F really nice and I made video on this problem.

Link https://youtu.be/3mnwcJGO_MI

If you have any suggestions, feel free to leave them below :)

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By RockyB, history, 4 years ago, In English

Hi everyone!

This is my second screencast, but this time with a webcam and some explanations at the end.

I am posting this blog because I truly believe that most of you will find this screencast helpful and educative.

Reasons why you should watch this:

  • To watch/learn how coders use stress test script to find bugs, sometimes to discover correct ideas to solution
  • To watch the explanation to the problems
  • To start using new cool IDE from the video
  • To watch me exciting and finally solving last problem on last minutes :D

Comments:

This time I performed much better than on previous screencast, so I hope you will enjoy this :)

UPD:

All of my solutions passed final system testing, however problem D was removed from the contest because of some issues with checker program (click).

Finally, ranked 47th among 18k+ participants.

Link to the screencast: https://youtu.be/w2ihLqN9hdg

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By RockyB, history, 4 years ago, In English

Hi everyone,

Recently I discovered Boruvka's Algorithm and I think this algorithm is really interesting. So I made a video lecture on this algorithm where I cover 2 problems related to it (1 standard and 1 relatively hard).

I hope that you will enjoy this video and learn something new. I worked very hard editing and making this video for 2 days, so make sure to subscribe to my channel and like the video :)

Here's the video click.

Comments:

I'm still working on the 2nd part of this video lecture where I'm explaining this problem CF 888G. As soon as this part will be ready, I will upload the video, so don't miss it.

Problems from the lecture

  1. MST
  2. Xor-MST

Problems from the readers

  1. Spanning Tree
  2. Kuroni and Antihype

UPD:

Any feedback is appreciated a lot. If you have any algorithms/concepts/tricks which you would like to see in the next videos, feel free to let me know in the comments below.

Thank you!

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By RockyB, 4 years ago, translation, In English

Hi!

I intend to start doing screencasts regularly so don't miss them.

Comments:

I didn't perform that brilliant, but anyway I think this screencast might be helpful, especially a part when I was debugging.

Hope you'll enjoy it :)

click

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By RockyB, 5 years ago, translation, In English

Hi everyone :)

Recently I started to work as CP tutor/coach, doing online lessons, though I have been teaching CP for several years. Probably CF is not that appropriate place to ask this (saying sorry), but I'm very curious how can I find english speaking students?

Some of the Olympiad achievements are 2 Gold Medals on Kazakhstan National Olympiad in Informatics, Gold Medal on the International Zhautykov Olympiad and Bronze Medal on the International Olympiad in Informatics.

FAQ:

  • Price: just reach me by private message to discuss the price
  • Teaching time: can teach any time you want (private message for details)
  • Requirements: anyone with passion to programming can join my lessons

Don't hesitate to PM in Telegram/Facebook or write an Email.

Thank you!

Please, don't downvote. Your care and attention will help me very much :)

UPD – 30/05/22: Now I work as a software engineer at Google, but I still do coaching. Some of my students made it to IOI, some more senior students got offers from big companies like Google, Microsoft.

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By RockyB, history, 5 years ago, translation, In English

Hi everyone :)

If you have proper and prior experience, could you give some advices in preparation for the IOI? On what should my concentration be to do well?

If probably you can't give any advice because these questions are too general I put some questions below.

  • How many hours did you prepare everyday to show your best on the IOI?
  • What type of problems did you solve?
  • What resources did you use?
  • Should I do some math stuff?
  • How to learn to solve problems which need a lot of observations, concepts?

Thank you so much!

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By RockyB, 7 years ago, In English

Hi everyone!

I made order on CodeChef, on october 31 and it was dispatched on november 8

Tracking service still does not work and support did not reply me

If you once made order, how much time did you wait?

Thank you in advance!

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By RockyB, 7 years ago, In English

I will write blog about my preparation.

You can see it here :)

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By RockyB, 7 years ago, translation, In English

Hi CodeForces!

In this blog written that in problems Divide and Conquer Optimization opt[i] <= opt[i + 1]

opt[i] -> such k that gives optimal answer, for example dp[i] = dp[k - 1] + C[k][i]

Please, can you explain why?

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By RockyB, 8 years ago, translation, In English

Hi CodeForces!

It's again me :D

For a long time i noticed such bug, when you open status of submissions and you can't open next page.

Please fix it.

UPD : fixed :)

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By RockyB, 8 years ago, In English
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By RockyB, 8 years ago, translation, In English

Hello CodeForces)

I was solving one problem, and a lot of time I couldn't understand why i got WA

WA code -> 
if (n > 1){
  if (Check(n)) Update(n, 1);
  else if ((ll)sqrt(n) * (ll)sqrt(n) == n) Update((ll)sqrt(n), 2);
}
AC code -> 
double x = n;
x = sqrt(x);
if (n > 1){
  if (Check(n)) Update(n, 1);
  else if ((ll)x * (ll)x == n) Update((ll)x, 2);
}

In first code if n = 302500001100000001 sqrt(n) = 550000000 but right is 550000001

I tryed to check in CodeForces custom test, it's error only in my and OJ compiler

Tell me why???

Give me some hint, how to upload photo in HQ???

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By RockyB, history, 8 years ago, In English
Tags bag
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By RockyB, history, 8 years ago, In English
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By RockyB, history, 9 years ago, In English

No rated contests, no sentiment

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