ago wrote: [Something I mostly agree with]
> According to Anton the number of possible solutions can be reduced > using 1) number swapping, 2) mirroring, 3) blocks/rows/columns > swapping. All those operations create equivalent matrices. For a 9X9 > grid, this should give a reduction factor = (9!)*(48)*(6^12) minus the > number of duplicated combinations given by the methods above. I am not > sure how to calculate the number of duplicated combinations and > therefore do not know if the result is "good enough". As mentioned, I > doubt that it is a viable approach, but I find it an intriguing > approach nevertheless. We could start hunting down net sites giving sudoku problems and claim they are trying to sell us the same problem twice :-) Or produce counterfeit problems ourselves and get rich quick. But I wonder about that 6^12 term. Within each 3-row block there are 6 permutations. There are 3 3-row blocks and 3 3-column blocks. Then between blocks (swapping complete 3-row blocks) permutations also give a factor 6. So in my count (but I suck at math) this term schould be: 6**8 (also switching to Python exponentiation notation) Anton -- http://mail.python.org/mailman/listinfo/python-list