mredigonda's blog

By mredigonda, history, 3 months ago, In English,

Hi, I will be helping in a Training Camp soon, we are going to use vjudge to use problems from various OJs like Codeforces, AtCoder, SPOJ, etc., and I noticed that there doesn't seem to exist a tool to transform problem statements into PDFs (which is really useful if you are trying to compose a problemset), the ones that exist are usually specifically tailored to a single platform, and some have problems with images, etc.

So I composed some quick and dirty (but simple) solutions, this is not a tool, but with enough effort it could be converted into one. This is the Github repo if you want to read it with Github's markdown, or if you want to contribute something. I will (almost) mirror what's the repo in this post, so you don't have to bother with that extra click.

Also, if you know a better tool, I would be glad to hear that I wasted my time because this is already done, so please tell me.

How to use

Go to the problem page, open the developer tools (F12 in Chrome), go to console, and paste the respective payload below, this will allow you to print the problem statement (you can then select to print it to PDF). All of these preserve images.

These codes delete the prefix letter of the problem since they might cause users to guess the difficulty of the problem, to make this completely effective, make sure to turn off priting "headers and footers".

AtCoder

var x = document.getElementById('main-container').children[0].children[1].children[0].innerHTML;
var y = document.getElementById('task-statement').children[0].children[1];
y.removeChild(y.children[0]);
document.body.innerHTML = '<h1>' + x.substr(x.indexOf('-') + 2) + '</h1>' + y.innerHTML;
window.print();

Codeforces

var x = document.getElementById('pageContent');
var y = x.children[2].children[0].children[0].children[0].children[0].innerHTML;
x.children[2].children[0].children[0].children[0].children[0].innerHTML = y.substr(y.indexOf('.') + 2);
document.body.innerHTML = x.innerHTML;
window.print();

SPOJ

var x = document.getElementById('problem-name').innerHTML;
var y = document.getElementById('problem-body').innerHTML;
document.body.innerHTML = '<h1>' + x + '</h1>' + y; 
window.print();

Problems

  • For SPOJ and AtCoder, it doesn't report the time and memory limits, since I'm planning on using vjudge, and that tells you those limits, I plan on getting people watch the limits from there, but you get the idea of how to extend this if you want to, I would, of course, welcome PRs.

  • I need support for other OJs, feel free to add yours.

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By mredigonda, history, 17 months ago, In English,

EDIT: Never mind, I found it. Yet the number on the problemset page (250) does not match the number of the contest (247).

Hello,

Currently it's not possible to submit solutions to problems of this contest, although we can see the statements. These problems do not appear in the problemset page neither.

Is this supposed to happen? :(

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By mredigonda, history, 3 years ago, In English,

There is a publication in this facebook page:

"Hello! We have some bad news. :( Visa-free regime will not be introduced. Sincerely apologize. It is not the fault of the Organizing Committee. On Monday we will publish the procedure for obtaining a visa. We ask you in the registration system to indicate the full address of the Consulate or visa centre where you intend to obtain a visa."

I think it's the official facebook page, since when I click on the facebook icon in this website it redirects me to that facebook page.

But there's no publication already about how to obtain the visa. I post this because I think that not everyone is aware of this, and I think it's very important.

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By mredigonda, history, 4 years ago, In English,

Hello Codeforces Community!

Some of you may remember that last year there was an online mirror of Lithuanian Olympiads in Informatics, from March 20th (practice session) to March 22th.

I really liked this contest, and I'd like to know if it is also going to be held this year, so if any of you know something about this, please tell me :) Thanks!

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By mredigonda, 4 years ago, In English,

Hello, i'm an OI contestant and recently I found a lot of problems like this one:

You have a n by n matrix, each cell is either 0 or 1. Find the maximum subsquare in which all the cells are 1.

This is the classic problem, but there are a lot of variants: find the maximum rectangle, find the maximum area of two consecutive subsquares, etc.

I know a solution in O(n^3) and I know there is a solution in O(n^2) but I can't understand it, can you please explain me how it works? or give me some resource to read about it?

Also I have a particular interest in "find the maximum area of two consecutive subsquares".

It'd be great if you can help me, thanks!

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