Contents
level: simple
| .......12....35......6...7.7.....3.....4..8..1...........12.....8.....4..5....6.. | initial |
| 673894512912735486845612973798261354526473891134589267469128735287356149351947628 | solved |
level: simple
http://theory.tifr.res.in/~sgupta/sudoku/algo.html