7th Contest of Newbies

[Observer]

7th Contest of Newbies
Date: December 31st, 2011 (Saturday)
Time: 12:00 - 16:00 (UTC)
URL: http://uva.onlinejudge.org

Hello, everyone! We are happy to announce that the 7th Contest of Newbies is to be held on UVa Online Judge on the last day of 2011. I would say it is one of the best ways to celebrate the coming of new year.

As in the previous contest, three tasks are considered "easy" and solvable even by new programmers.

For a taste of what our problems are like, here are some highlights of our old tasks:

Easier:
10976 - Fractions Again?!
11152 - Colourful Flowers

Harder:
10817 - Headmaster's Headache
11374 - Airport Express
11570 - Sudoku without numbers?
11914 - An Amazing Race

We look forward to your participation and support. You are of course welcome to promote this contest to your friends~

[EDIT] For Facebook users:
http://www.facebook.com/events/204195869660292/

[Observer]

Special thanks to the 100+ teams who took part in the 7th Contest of Newbies! The six problems are now available on the 24h Online Judge, with number 12397-12402.

For your reference, here are the last-hour hints (slightly modified) given on the clarification board:
"
A-C are easier - just go the simple way.

A. You can find Roman conversion codes via Wiki.
B. Do increment instead of decrement.
C. Some brute-force method works!
-------------------------------------------
D. Can you solve it with N=M=K?
E. Consider Fibonacci numbers.
F. Judge solution uses a search and has more than 200 lines.
"