CodeChef is a non-commercial competitive programming community
Login
Username (New User? Signup) Password (Forgot Password?)
Signup
Login or
Signup with
Connect
Note
  • Publicize your achievements on your Facebook Wall.
  • Challenge your friends or ask them for help.

Site Navigation

  • PRACTICE
    • Easy
    • Medium
    • Hard
    • Challenge
    • Peer
  • COMPETE
    • February CookOff
    • February Long Contest
    • January CookOff
  • DISCUSS
    • Wiki
    • Forums
    • Blog
    • Twitter
  • COMMUNITY
    • CodeChef Meetups
    • Campus Chapters
    • Host your Contest
    • User Groups
    • CodeChef TechTalks
    • All Educational Initiatives
    • Event Calendar
  • HELP
    • Frequently Asked Questions
    • FAQ for problem setters
    • Problem Setting
    • Ranks
    • Tutorials
  • ABOUT
    • About CodeChef
    • Team CodeChef
    • Press Room
    • CodeChef Financials
    • CodeChef Sponsorships
    • CEO's Corner
    • Contact Us
    • About Directi
Home » Compete » March 2009 (Contest I)  » Place the mines!

Place the mines!

Problem code: AX

  • All Submissions

The following a tie breaker problem. The best answer will receive one point. All other successful answers will be scored on a curve and receive a fraction of a point based on how close they come to the best answer.

You are given a large square area with an edge length of 2n, subdivided into unit squares (fields). Some mines have already been planted on certain fields, and we would like to plant as few more mines as possible, so as to destroy all of the fields of the area (assuming all the mines explode simultaneously). For each mine, the fields it destroys are given as follows. For any k , 0 <= k <= n, we can partition the considered area into 2n rectangles of size 2k x 2n-k. The mine is assumed to destroy a square if and only if the mine and the square belong to the same rectangle in the considered partition, for some value of k.

For example, if n=3, the mine "*" placed on the square at position (1,1) will destroy all the fields which are not marked with dots below:


.#......
.#......
.#......
.#......
##......
##......
#*######
####....

Input

The first line will contain integer 8<=n<=16, (where 2n is the size of the area). The second line will contain 0<=m<2n, the number of already planted mines.
The next m lines will contain the 0-based x and y coordinates of the existing mines.

Output

The first line should contain t - the number of mines to be added.
The next t lines should contain the coordinates of the added mines.

Scoring

For each test case, you will receive (2n-m)/t-1 points, provided you destroy all the fields of the area.

Example

Input:
2
1
3 3

Output:
2
0 1
2 2

You will receive (4-1)/2 - 1 = 0.5 pts for such a mine placement.

Note:
There will be some tests with no initially placed mines, and some tests with initial placements covering most of the area pretty well. Good luck!


Date: 2008-12-01
Time limit: 5s
Source limit: 50000
Languages: C C99 strict C++ PAS gpc PAS fpc JAVA NICE JAR C# C#2 NEM ST ASM D FORT ADA BASH PERL PYTH RUBY LUA ICON PIKE PHP SCM guile SCM qobi LISP sbcl LISP clisp HASK CAML CLPS PRLG WSPC BF ICK TEXT


  • Submit

Comments

  • Login or Register to post a comment.

SUCCESSFUL SUBMISSIONS FOR THIS PROBLEM:

Programming Competition Fetching successful submissions
Directi Go for Gold
CodeChef is a global programming communityCodeChef hosts online programming competitions
CodeChef is a non-commercial competitive programming community
  • About CodeChef
  • About Directi
  • CEO's Corner
  • C-Programming
  • Programming Languages
  • Contact Us
© 2009 Directi Group. All Rights Reserved. CodeChef uses SPOJ © by Sphere Research Labs
In order to report copyright violations of any kind, send in an email to copyright@codechef.com
CodeChef a product of Directi
The time now is:
CodeChef - A Platform for Aspiring Programmers

CodeChef was created as a platform to help programmers make it big in the world of computer programming. At CodeChef we work hard to revive the geek in you by hosting programming contests on a monthly basis. We also aim to have training sessions and events related to online programming for programmers around the world. Apart from providing a platform for programming competitions, CodeChef also has various tutorials and forum discussions to help those who are new to the world of computer programming.

Practice Section - A Place to hone your 'Computer Programming Skills'

Try your hand at one of our many practice problems and submit your solution in a language of your choice. Our judge accepts solutions in over 35+ programming languages. Online programming was never this much fun! Receive points, and move up through the CodeChef ranks. Use our practice section to better prepare yourself for the multiple programming competitions that take place through-out the month on CodeChef.

Compete - Monthly Programming Contests and Cook-offs

Here is where you can show off your computer programming skills. Take part in our 10 day long monthly programming contests and the shorter format Cook-off programming contests. Put yourself up for recognition and win great prizes. Prizes worth up to Rs.20,000 and $700 are up for grabs every month along with lots more CodeChef goodies.

Discuss

Are you new to computer programming? Do you need help with algorithms? Then be part of CodeChefs Forums and interact with all our programmers love helping out other programmers and share their ideas.

CodeChef Community

As part of our Educational initiative, we give institutes the opportunity to associate with CodeChef in the form of Campus Chapters. Hosting online programming competitions is not the only feature on CodeChef. Be a part of the CodeChef community through CodeChef meetups and techtalks. You can also host a programming contest for your institute on CodeChef and be a guest author on our blog.

Domain Name Registration, Web hosting, and Website Design provided by BigRock.com