Week of code 29th edition https://www.hackerrank.com/w29 is starting tomorrow February 20th 7:00 am UTC.

Monday to Sunday every day 1 challenge will go live. (Easy to Hard) To get the full score for a challenge, you need to solve it within 24 hours of the time when it goes live. At the end of every 24 hours score for each published challenge decreases by 10%.

I experience some strange issue trying to use formulas in Codeforces blog post.

The steps to reproduce: go to your profile, press "Write new entry", place dollar sign character, then sh (two characters), then dollar sign character into content field (total four characters) and then press Preview button.

Expected behaviour: italized sh in preview.

Observed behaviour: Unable to parse markup [type=CF_TEX] message in preview.

What am I doing wrong and what to do about it? I tried to post an article containing many formulas and was not able to do it. I reduced it to the smallest test case. Several other two-letter combinations produce a strange result too.

A. Again Twenty Five!

The problem of getting the last two digits is equivalent to the problem of getting the number modulo 100. So we need to calculate . According to

Hello, Codeforces!

“Experimental Educational Round: VolBIT Formulas Blitz” will take place on February 18, 2016 at 18:00 MSK. This time the problemset is recommended for Div.2 participants.

The round will be unrated for all users and it will be held according to the standard ACM-ICPC rules. You will have 180 minutes (three hours) to solve 18 problems. There will be no open hacks phase after the round.

Our main target audience is beginners and Div. 2 members. All offered problems can be solved without conditional constructs and without loops. Only formulas are required. Assignments and functions can be used to reduce code duplication.

The topics of the problems are:

• combinatorics
• geometry
• game theory
• sequences
• other

The round is created as a part of Vologda BIT event, also as part of this event “Contest programming from zero in Java” webinars were held devoted to the topics listed above. Recordings of the webinars are available on YouTube (in Russian).

The round was prepared by me, Fyodor Menshikov mfv, Igor Andrianov igand and Oleg Strekalovsky OSt. Special thanks to Maria Belova Delinur for bugfixing the English statements and of course to MikeMirzayanov for Codeforces platform and Polygon. Polygon made our checkers and tests for this contest better.

UPD: The editorial is complete.