[i_s]

Here is one in Swift I did a few years ago that does:

https://github.com/isaksky/sudoku-swift/blob/master/Sudoku-S...

This one solves all 50 from Euler: https://projecteuler.net/problem=96

And here is a classic one in Python from Norvig:

http://norvig.com/sudoku.html

[emmanuel_1234]

Shameless plug, my OCaml implementation: https://github.com/eprochasson/norvig-ocaml