Competitive-Programming

This post was originally written on Codeforces; relevant discussion can be found here. I’ve been involved with testing a lot of Codeforces contests and coordinating contests for my uni, and have seen various kinds of issues crop up. However, I was able to come up with a stable system for my uni contests that helped make the experience as educational and error-free as possible, and I have found the lack of some of those things to be the main reason behind issues faced by Codeforces contests. ...

This post was originally written on Codeforces; relevant discussion can be found here. Disclaimer: This is not an introduction to greedy algorithms. Rather, it is only a way to formalize and internalize certain patterns that crop up while solving problems that can be solved using a greedy algorithm. Note for beginners: If you’re uncomfortable with proving the correctness of greedy algorithms, I would refer you to this tutorial that describes two common ways of proving correctness — “greedy stays ahead” and “exchange arguments”. For examples of such arguments, I would recommend trying to prove the correctness of standard greedy algorithms (such as choosing events to maximize number of non-overlapping events, Kruskal’s algorithm, binary representation of an integer) using these methods, and using your favourite search engine to look up more examples. ...

This post was originally written on Codeforces; relevant discussion can be found here. This post was initially meant to request updates to the C compiler on Codeforces (given the large number of posts complaining about “mysterious” issues in their submissions in C). While writing it, I realized that the chances of the said updates would be higher if I mentioned a few reasons why people would like to code in C instead of C++ (some of the reasons are not completely serious, as should be evident from the context). ...

This post was originally written on Codeforces; relevant discussion can be found here. Since someone recently asked me about my competitive programming setup, and I like tinkering with my setup to make it as useful and minimal as possible, I thought I should share my setup that I’ve used for the past few years and a modified version that I’ve used at onsite ICPC contests. I’ve also talked to a few people who went to IOI and had a similar setup, and I’m fairly confident that at least some people will be able to successfully use this without having to worry too much about the details, like I did. This is definitely NOT the only way to set up a basic environment, but it was the way that worked for me for quite a long time. ...

This was written jointly by errorgorn and me and published on errorgorn’s blog, and the original post is here. You can also check out his personal blog here. Hi everyone! Today nor sir and I would like to talk about generating uniform bracket sequences. Over the past few years when preparing test cases, I have had to generate a uniform bracket sequence a few times. Unfortunately I could not figure out how, so I would like to write a post about this now. Hopefully this post would be useful to future problem setters :) Scroll down to the end of the post to copy our generators. ...

We ended up making a meme contest, here’s the announcement for the contest; the original announcement is here. Hi Codeforces! We are pleased to invite you to [contest:383377], which will take place on [contest_time:383377]. You will be given 9 problems and 2 hours to solve them. Please follow this link in order to register for the contest. Note that this contest is not an official Codeforces round. The round will be unrated for all participants. It will be held according to modified ICPC rules. ...