The New Sudoku Players' Forum

[shea89]

Hi guys, I'm making a sudoku solver which can only use techniques and not brute force/backtracking, I have a number of techniques implemented in my program but I'm kind of stuck on what technique to use next.

I have a sample of 10 random hard puzzles and at the moment I'm completely solving 6 of them could someone have a look at my partially completed puzzle (possible candidates included) and maybe show me the next technique to code.

puzzle is http://i43.tinypic.com/zugnlh.png

This would be a great help thanks.

[JC Van Hay]

There is a Naked Quad in row 8

[shea89]

Thanks so much I've now coded naked quads and naked triples I'm now solving 9/10 puzzles from my sample pool, the last puzzle is this one http://i44.tinypic.com/2ibkqqq.png

could you please tell me the technique needed to complete his puzzle?

Thanks,
Shea.

[JasonLion]

That is a simple Locked Candidates (claiming): row 8 -> block 9 on 4 leading to a solution with singles only.

[shea89]

thanks guys I'm successfully solving my sample hard puzzles now, thanks for all your help I understood the techniques but just didn't have the skill to notice which ones should be applied

Thanks again,
Shea