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A coder likes riddles like coding. Unlike my post about the number of zeros at the end of the result of 1000! this post does not even have any code in it. I found a post about a sudoku which is supposed to be the most difficult of its kind, check this link for more information: http://www.chinaabout.net/69-year-old-chinese-farmer-answer-difficult-sudoku-world/.

There’s one solution in the article, the second one is missing. Suspicious how I am, I had to check if there’s a second solution. It turns out there is, here’s my solution:

8 1 2 | 7 5 3 | 6 4 9
9 4 3 | 6 8 2 | 1 7 5
6 7 5 | 4 9 1 | 2 8 3
------+-------+------
1 5 4 | 2 3 7 | 8 9 6
3 6 9 | 8 4 5 | 7 2 1
2 8 7 | 1 6 9 | 5 3 4
------+-------+------
5 2 1 | 9 7 4 | 3 6 8
4 3 8 | 5 2 6 | 9 1 7
7 9 6 | 3 1 8 | 4 5 2

What I don’t understand is how one knows whether it’s the most difficult sudoku. Anyone knows more than I do?