This popular Japanese number puzzle has just one easy rule: In every Row, every Column and every 3x3 sub-grid, all the numbers from 1 to 9 should appear, but only once in each row, column and sub-grid.
+------+-------+------+
| 0 0 0 | 7 0 0 | 4 0 0 |
| 0 3 0 | 0 9 0 | 0 2 0 |
| 4 0 0 | 0 0 5 | 0 0 0 |
+------+-------+------+
| 0 0 8 | 0 0 0 | 0 0 5 |
| 0 9 0 | 0 3 0 | 0 7 0 |
| 6 0 0 | 0 0 0 | 3 0 0 |
+------+-------+------+
| 0 0 0 | 4 0 0 | 0 0 6 |
| 0 7 0 | 0 2 0 | 0 9 0 |
| 0 0 5 | 0 0 8 | 0 0 0 |
+------+-------+------+

Replace the 0's with the digits required to satisfy the rule.

(In reply to re(3): For those who don't know... by Penny)

Penny, I respect your point of view, and perhaps you are misunderstanding me. That's not my intention.

I myself (I'm from the age of dinosaurs - the personal computers at that time didn't arived here in Brasil ) used programming (Cobol, Assembler, Fortran, etc...) to write algoritms to enable a friend to play "The game of Nim" against the computer, or even, to look for the answer to an old puzzle with four cubes, with colored faces, or another difficult puzzles, all hard to be solved.

And this was very good for me, since it helps me to improve my sense of logical thinking.

Unfortunatelly (although my professional work today doesn't need it), I don't know nothing involving programming with the new languages (VB or C or C++, etc...) for micros, and because of this (and only for this) I prefer those "puzzles" who needs only pencil and paper (and of course, a lot of reasoning). Even those problems that the solution could be achieved with "trial and error" doesn't attract me.

And, since you named Plato, I'm wondering (if it's indeed true, and not a mistake of him), how could Fermat prove his last teorem, with the knowledge that they have at that time about number theory. The prove achieved a few years ago, is far from being understandable for 99% of those who leads only with math.

Best wishes !

 

 

 

Posted by pcbouhid on 2005-05-15 23:35:18