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.

Hugo,

Nice problem. In fact, I know this kind of puzzle, and I don't tell its name here for obvious reason (search in internet).

I'll try to solve it.

My first contribution is to put two numbers that doesn't need much to think. They are the 4 in the second block, and the 3 in the fourth block.

<TABLE style="WIDTH: 144pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=192 border=0 x:str> <COLGROUP> <COL style="WIDTH: 48pt" span=3 width=64> <TBODY> <TR style="HEIGHT: 12.75pt" height=17> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; WIDTH: 144pt; BORDER-BOTTOM: #e0dfe3; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" width=192 colSpan=3 height=17>+------+-------+-----+</TD></TR> <TR style="HEIGHT: 13.5pt" height=18> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 13.5pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=18>| 0 0 0 | 7 0 0 | 4 0 0 |</TD></TR> <TR style="HEIGHT: 18pt" height=24> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=24>| 0 3 0 | 0 9 4 | 0 2 0 |</TD></TR> <TR style="HEIGHT: 18pt" height=24> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=24>| 4 0 0 | 0 0 5 | 0 0 0 |</TD></TR> <TR style="HEIGHT: 18.75pt" height=25> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18.75pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=25>+------+-------+-----+</TD></TR> <TR style="HEIGHT: 18pt" height=24> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=24>| 3 0 8 | 0 0 0 | 0 0 5 |</TD></TR> <TR style="HEIGHT: 18pt" height=24> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=24>| 0 9 0 | 0 3 0 | 0 7 0 |</TD></TR> <TR style="HEIGHT: 18.75pt" height=25> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18.75pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=25>| 6 0 0 | 0 0 0 | 3 0 0 |</TD></TR> <TR style="HEIGHT: 18pt" height=24> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=24>+------+-------+-----+</TD></TR> <TR style="HEIGHT: 18pt" height=24> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=24>| 0 0 0 | 4 0 0 | 0 0 6 |</TD></TR> <TR style="HEIGHT: 18.75pt" height=25> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18.75pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=25>| 0 7 0 | 0 2 0 | 0 9 0 |</TD></TR> <TR style="HEIGHT: 12.75pt" height=17> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=17>| 0 0 5 | 0 0 8 | 0 0 0 |</TD></TR> <TR style="HEIGHT: 12.75pt" height=17> <TD class=xl22 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; mso-ignore: colspan" colSpan=3 height=17>+------+-------+-----+</TD></TR></TBODY></TABLE>

Posted by pcbouhid on 2005-05-13 19:56:30