Sudoku solver

[Chris Angelico]

On Thu, Mar 26, 2015 at 7:31 AM, Marko Rauhamaa <marko at pacujo.net> wrote:
> Ian Kelly <ian.g.kelly at gmail.com>:
>
>> The test puzzle that you posted has 23 values already filled in. How
>> does it perform on harder puzzles with only 17 clues (the proven
>> minimum)? One would expect it to be around a million times slower.
>
> Just try it. The example had a minimum of clues (drop one clue and
> you'll get multiple solutions).

That's not quite what Ian meant. You've shown that your particular
grid needs every clue to be solvable; Ian is pointing out that it's
possible to create a solvable puzzle (one with a unique solution) with
only 17 clues.

ChrisA