Golovanov399's blog

By Golovanov399, history, 7 weeks ago, In English,

Hello everyone,

Some of you may know about recently discovered vulnerabilities (well, technically, there in one vulnerability and two attacks using it). I am not a cybersecurity expert, I know what is going on about the "read-all-those-breaking-news-titles" level, but as I understood, some things can slow down by 30%. So I have a couple of questions:

  1. Do testing systems like codeforces, yandex.contest, topcoder, atcoder, csacademy etc apply the patch? I don't know if testing machines store something that is important and shouldn't be stolen.

  2. If yes, does this mean that we now should multiply all time limits by 0.7? Maybe this coefficient is not so small because 30% is reached on some other type of operations which are not used in cp? On the other hand, branch prediction is used almost always in cp, as I know.

Somebody who knows how this works, answer, please.

Read more »

  • Vote: I like it  
  • +89
  • Vote: I do not like it  

By Golovanov399, 6 months ago, In English,

Hello, everyone.

I guess that those of you who doesn't solve problems only in his mind use pen and paper to make some notes, eg draw graphs, points, lines, permutations, shortly, everything. It's very convenient, but there are tools on the internet that make this process more comfortable in several cases: for example, a graph editor or a geometry widget (there was a nice page by zxqfl, but it seems to be expired or something). All these services allow to obtain visualizations from some (debug-)print-friendly format, which can save your time.

Once I decided to write a tool for drawing grids (as I remember, it was approximately when I was solving the task from the last russiancodecup). You can find it here. Some usecases are also provided. The default text in the textfield is a brief manual, but you can type something and see what happens.

Below you can see an example of usage (based on the problem from rcc above):

Maybe (not very likely) some new functionality will be added. You can copy and modify any code you'll find.

Read more »

  • Vote: I like it  
  • +148
  • Vote: I do not like it