Sudoku Programmers Forum Index

 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister   ProfileProfile   Log inLog in          Games  Calendar

Log in to check your private messagesLog in to check your private messages   

When can multiple fins exist?

 
Post new topic   Reply to topic    Sudoku Programmers Forum Index -> Solving sudoku
View previous topic :: View next topic  
Author Message
MCondron

Joined: 17 Jul 2006
Posts: 35
:
Location: Houston, TX

Items
PostPosted: Thu Dec 21, 2006 1:15 am    Post subject: When can multiple fins exist? Reply with quote

I just want to make sure I have something right here regarding multiple fins. First, to be completely clear, by "multiple fins" I mean fins in more than one box, not "big fins", which is more than one fin in a single box.

It seems to me that multiple fins are NOT possible in "standard" (non-mutant) fish. They are only possible in mutant fish, right? What about franken-type configurations? Question
Back to top
View user's profile Send private message
rkral

Joined: 21 Oct 2005
Posts: 233
:

Items
PostPosted: Thu Dec 21, 2006 2:29 am    Post subject: Re: When can multiple fins exist? Reply with quote

MCondron wrote:
It seems to me that multiple fins are NOT possible in "standard" (non-mutant) fish. They are only possible in mutant fish, right? What about franken-type configurations? Question

Good questions! Multiple fins -- fins that yield exclusions -- are not possible with basic fish defined only by rows and columns.
Code:

 .  /  . |  .  /  . |  .  /  .
 *  X  * |  *  X  * |  *  X  *
 .  /  . |  .  /  . |  .  /  .
---------+----------+----------
 .  #  . |  .  /  . |  .  /  .
**  X ** |  *  X  * |  *  X  *
 .  #  . |  .  /  . |  .  /  .
---------+----------+----------
 .  /  . |  .  /  . |  .  /  .
 *  X  * |  *  X  * |  *  X  *
 .  /  . |  .  /  . |  .  /  .
 finned swordfish


Basic fish are NxN constraint sets -- N base rows with N covering columns (or N base columns with N covering rows). The rows and columns are orthogonal.

A fin cell (#) can only exist at a required empty cell (/) of the unfinned fish. An exclusion cell for a finned fish (**) can only occur at an exclusion cell of the unfinned fish (* and **).

An exclusion cell must "see" all the fin cells. Since rows and columns are orthogonal, an exclusion cell can only see fin cells within its own box.

Fin cells for finned franken and mutant fish can occur in multiple sectors.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Sudoku Programmers Forum Index -> Solving sudoku All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Sudoku Programmers topic RSS feed 


Powered by phpBB © 2001, 2005 phpBB Group

Igloo Theme Version 1.0 :: Created By: Andrew Charron