How are killer sudokus created?

For fans of Killer Sudoku, Samurai Sudoku and other variants

How are killer sudokus created?

Postby dyitto » Mon Nov 15, 2010 9:13 pm

How are killer sudokus created?

What I'm trying now is:

- define some cages with undefined totals
- generate a grid such that no number occurs twice in such a cage
- compute the cage totals from the grid
- empty the grid
- see if the current cages and cage totals allow at most one solution

There are always more solutions. Now my program is running a scenario and still no answer after an hour. :(
evert on the crashed forum
User avatar
dyitto
 
Posts: 118
Joined: 22 May 2010
Location: Amsterdam

Re: How are killer sudokus created?

Postby dyitto » Thu Nov 18, 2010 10:47 pm

I tried a more 'gradual' approach:

Define cages with unknown totals.
(A valid grid is supposed to have at least unique numbers in each cage.)

For each cage:

Generate some valid grids and calculate the corresponding totals for that cage.
If some total appears to be higher, lower or more rare then average, then stick to that total for that cage.

Then go on to the next cage etc.

I stumbled upon this one:

Image

It needs few guesses. I've also checked it with JSudoku.
For three of the cages, knowledge of the total is not essential for uniqueness of the solution.
Last edited by dyitto on Sun Aug 12, 2012 9:11 am, edited 1 time in total.
evert on the crashed forum
User avatar
dyitto
 
Posts: 118
Joined: 22 May 2010
Location: Amsterdam

Re: How are killer sudokus created?

Postby tarek » Fri Nov 19, 2010 10:41 pm

Hi dyitto,

Redundant cages can be removed ... but it is not a must .. you can make a similar comparison with minimal and non minimal vanilla sudoku. both are playable & legal.

A minimal killer:
If ANY sum constraint is made unknown then the puzzle would have multiple solutions

IMO, Killer puzzle designers should attempt the following if possible to achieve a better design:
1. All cells should be covered with sum constraint cages.
2. No single cell cage sum (i.e. No killer with vanilla style given(s))

tarek
User avatar
tarek
 
Posts: 2624
Joined: 05 January 2006

Re: How are killer sudokus created?

Postby HATMAN » Wed Nov 24, 2010 10:13 am

Of course if you disobey the first rule Tarek mentions it is called a zero killer, see:

http://www.rcbroughton.co.uk/sudoku/for ... ?f=3&t=848
HATMAN
 
Posts: 204
Joined: 25 February 2006

Re: How are killer sudokus created?

Postby dyitto » Thu Nov 25, 2010 5:22 am

Hi Hatman, your link doesn't seem to work.
evert on the crashed forum
User avatar
dyitto
 
Posts: 118
Joined: 22 May 2010
Location: Amsterdam

re: "Zero Killer"

Postby Pat » Thu Nov 25, 2010 8:26 am

User avatar
Pat
 
Posts: 3449
Joined: 18 July 2005

Re: How are killer sudokus created?

Postby HATMAN » Sat Dec 04, 2010 12:59 pm

Thanks Pat
HATMAN
 
Posts: 204
Joined: 25 February 2006


Return to Sudoku variants