Author Archives: pkacprzak


Codechef June Lunchtime 2017

On Saturday, Codechef June Lunchtime 2017 took place. I wrote the editorials for the contest and have to tell you that at least 2 problems were quite interesting, and one of them exceptionally hard! If you take a look at the final standings, you'll see that only 3 people solved all problems during the contest, and we had very strong participants as usual. My bet was that nobody will solve it, but fortunately, I was wrong :)

If you didn't participate and want to practice problem-solving skills, I recommend trying COMPCLUB problem, or if you want something really hard, then try SHDWCMP.

My editorials are available here.

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My participation in Codechef June 17 Long Contest


Codechef June 17 has just finished. After a few months of my inactivity in Codechef Long contests, caused by helping in preparing these contests, I took part in this one.

It turned out to be a fun contest with decent problems. I especially liked CLONEME problem and also ES - I'm not math expert by any means, so I got to put some unusual effort to solve it :D Challenge problem SABOTEUR was also nice, but I regret I didn't put enough effort there. I also regret not tackling the OAK problem.

I finished 34th, which is my second best result there I think, and this resulted in jumping to the top rank in Poland in the overall ranking. I'll try next month to beat that result.

If you have any questions regarding the problems from the contest or my approaches to them, I'd be happy to answer them.

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HackerRank Ad Infinitum 18

On June 9, HackerRank Ad Infinitum 18 has started. It is a math-oriented programming contest. There are 7 problems to solve, and I had a pleasure to prepare 2 of them.

If you like math and haven't joined the contest yet now it's time to do it :)  It's a rare opportunity for math lovers.

It's a rather rare opportunity for math enthusiasts. The next edition is planned in around 3 months from now.


SnackDown Online Pre-elimination round A

SnackDown 2017, Codechef's most important contest of the year takes place right now.

Over 12 000 teams advanced from the qualifier round to pre-eliminations rounds. Today first pre-elimination round A started and it'll end in around 14 hours.

There are 6 problems to solve in this round, and at least 5 are interesting. Top 1000 teams from this round will advance to the last Elimination Round, from which around 50 top teams will move to the onsite finals!


This time I'm not involved in contest preparation, but I'm participating in the contest :) Since this is a team contest I paired with my friend Tong Wei. However, when the contest started he was sleeping, so I took care of all these problems ;) We have all problems solved, so we are tied for 1st place, so for sure we'll advance to the next round.

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If you need any clues for approaching the problems (after the contest) just let me know.

See you in the next round!




Codechef April 17 Long


Codechef April 17 Long Challenge has started today and I'm happy that my problem Stable Market is one of the problems in the contest. This is the first time I created a problem for a Codechef Long Challenge, and moreover, it's quite interesting one, so I'm excited to see your submissions :D