Adam Shelly wrote:
...
And it took a while to figure out that this one was unsolvable:
+-------+-------+-------+
> _ 2 _ | _ _ _ | _ _ _ |
> _ _ _ | 6 _ _ | _ _ 3 |
> _ 7 4 | _ 8 _ | _ _ _ |
+-------+-------+-------+
> _ _ _ | _ _ 3 | _ _ 2 |
> _ 8 _ | _ 4 _ | _ 1 _ |
> 6 _ _ | 5 _ _ | _ _ _ |
+-------+-------+-------+
> _ _ _ | _ 1 _ | 7 8 _ |
> 5 _ _ | _ _ 9 | _ _ _ |
> _ _ _ | _ _ _ | _ 4 _ |
+-------+-------+-------+
Euh ... mmm....
my program tell me that is one has unique solution ( on 16.672 seconds )
ยทยทยท
+-------+-------+-------+
1 2 6 | 4 3 7 | 9 5 8 |
8 9 5 | 6 2 1 | 4 7 3 |
3 7 4 | 9 8 5 | 1 2 6 |
+-------+-------+-------+
4 5 7 | 1 9 3 | 8 6 2 |
9 8 3 | 2 4 6 | 5 1 7 |
6 1 2 | 5 7 8 | 3 9 4 |
+-------+-------+-------+
2 6 9 | 3 1 4 | 7 8 5 |
5 4 8 | 7 6 9 | 2 3 1 |
7 3 1 | 8 5 2 | 6 4 9 |
+-------+-------+-------+