- Code: Select all
+-------+-------+-------+
| 1 . . | . . . | . . . |
| . . . | . . . | . 3 . |
| . . 2 | 4 . 6 | 8 . . |
+-------+-------+-------+
| . . 8 | 6 . 2 | 4 . . |
| . . . | . . . | . . . |
| . . 6 | 8 . 4 | 2 . . |
+-------+-------+-------+
| . . 4 | 2 . 8 | 6 . . |
| . 7 . | . . . | . . . |
| . . . | . . . | . . 5 |
+-------+-------+-------+
1...............3...24.68....86.24.............68.42....42.86...7...............5
The following pairs of cells contain consecutive digits: r1c56, r2c23, r23c2, r23c5, r45c9, r56c1, r78c5, r78c8, r8c78, r9c45.
I'm not sure how hard this. It does have a unique solution.