## how many solutions?

Everything about Sudoku that doesn't fit in one of the other sections

### how many solutions?

hi everyone...I have to make a sudoku program for a school homework, so i need to know a few things, for example: how many solutions exist for a given puzzle, and how do I find each one of them, are there puzzles which do not have any solutions?, how do i design a puzzle acording to a certain level of difficulty?
chapis

Posts: 2
Joined: 20 April 2006

### Re: how many solutions?

May i suggest you try solving some fiendish sudokus and see what techniques you use to solve them.

The minimum number of clues in a sudoku is 17 (at present, not officially confirmed but widely suspected to be true) so any grid with less than 17 clues will not have a unique solution.
Most people solve a sudoku on the assumption that there is one solution, and can logically deduce the answer

chapis wrote:hi everyone...I have to make a sudoku program for a school homework

Its new to me that teachers expect you to produce a sudoku program, what school do you attend
Crazy Girl

Posts: 189
Joined: 08 November 2005

Hey, thanks you...I'm studying my first semester of Industrial Engineering at the University...(Rafael Landivar...in Guatemala)...and...teah I was amazzed too, but...now I talked to my teacher and he told me that my game doesn't has to be THAT perfect, but thanks anyway....
chapis

Posts: 2
Joined: 20 April 2006

a puzzle should have only one solution.

You can make simple puzzles with only one solution, that require only hidden and naked singles to solve. Even puzzles that require only naked singles to solve.

The first thing to try is making a simple solver that uses only singles then you can always add extra techniques
ab

Posts: 451
Joined: 06 September 2005