While waiting for API to update, (it has been updated already) let's look at hacks in Codeforces Round 281 (Div. 2). That was really good round (even I had some hacks :)).

Previous posts can be found here.

Brief stats about some past contest — Codeforces Round 280 (Div. 2).

Previous posts can be found here.

Hello and welcome in Codeforces Round 279 (Div. 2) — description of hacks.

Previous posts can be found here.

Waiting for next round, let's take some time and look at hacks in Codeforces Round 278 (Div. 1). That was really good round for hackers :)

Previous posts (including post for Div. 2.) can be found here.

Welcome in hacks' statistics in Codeforces Round 278 (Div. 2). That was really nice round for hackers! Many possibilities, many hacks, let's have a look!

Post for Div. 1. contest will be added later (there are pretty many hacks to parse :)) is here.

Previous posts can be found here.

Your comments are always welcome.

Welcome after the long break in Hack me! (Codeforces Round 277.5 (Div. 2)).

Previous posts can be found here.

Today has finished the 2014 Central Europe Regional Contests.

Update: the contest is now at Codeforces' gym: 100543.

API method which I really like using (contest.hacks) is not working since few days. I tried on several computers being logged in and out and from friends accounts and I am still getting message known to all of you: Codeforces is temporary unavailable...

Link to check: contest.hacks?contestId=474.

What is funny is that other methods and other contests are working. Try contest.hacks?contestId=475 or user.info?handles=illi.

Update: everything is working fine now -- with many thanks to Codeforces team!

Welcome in Bayan 2015 Contest Warm Up hacks description. This round was pretty good for hackers, but again there were nearly two times more unused opportunities for hack than the used ones. Let's look at them.

If you want to share your hack (or mistake) -- we're waiting for your comments.

Previous posts can be found here.

Welcome after the long break in hacks' describtion in Codeforces Round 270.

This round had really good pretests, so we didn't have many hacks (81 successful ones), but let's have a look at them.

Hey there! I am testing some new stuff (according to your suggestions) and playing with matplotlib (learning it to be precise), so here is a bunch of statistics (only) in some past contest (Codeforces Round 269 (Div. 2)).

Previous posts can be found here.

Quick message about why there were no posts covering hacks in last few rounds.

I have been asked for some people why there is no more posts about hacking, and I really have to apologize about it. I had some serious problems with hardware (simply I shouldn't have drunk next to my laptop :(), but now it looks like nearly everything is working fine.

I will try that for the next round (269) everything should be back. Maybe I will also try to cover passed rounds.

Again I am really sorry and thanks for asking!

FAQ

What is this?

Have you ever wondered who is the best hacker on Codeforces? Here is simple solution, which would try to answer for your problem! I would like to introduce new system of grading hackers in rounds.

Stats about hacks in Codeforces Round 263 (Div. 1) (quite late).

Welcome again!

I decided to split statistics for both division. Post for first division will be added later is here.

So, let's look at hacks in Codeforces Round 263 (Div. 2).

Some statistics are missing — I have some problems with downloading all data (Codeforces seems little crowded today). They will be also added later.

Update: Europe went asleep, so I added missing stats.

Hey, I wanted to start new series about hacking. I think that this part of programming contests is really underrated, but can be helpful for both people solving problems (you should know what tricky cases you need to consider) and people writing problems (you should know how to write nice tests covering everything).

So in this series, which I will try to continue, I will talk over hacks at Codeforces Rounds. I will try to do some statistics and take a look at most common mistakes in passing contests.

It is my first article related to hacking (and first at all :)), so feel free to suggest something, correct me on some errors or mistakes (my English still can be much better :)) and tell about your hacks. Thanks in advance!

So let's move to Codeforces Round 262 (Div. 2).

Update: added country wise statistics (at the end).

Update: added chart with hacks over time and first hacks.

Update: the handles are now full of colours, with many thanks to awesome accidentallygivenfuck!

Update: added section "biggest gap" (between rating of the hacker and defender).