In file "sudoku.dat" is 9x9 size matrix. In one 3x3 bloc, can be from 2 up to 6 unknew digits, however main unknow digits amount in all matrix, must be not over 36 digits.

Unknow places marked with symbol ?

Example (3x3)

?9?

4??

?32

I need program which could write, does mentioned matrix has solution according by by traditional sudoku rules, if yes solve that sudoku.

Thanks