udosuk (on Sat Dec 27, 2008 6:34 pm) wrote:But you don't need that little cycle - only the XY-chain is required:
- Code: Select all
+-------------------+-------------------+-------------------+
| 189 6 3 | 2 189 19 | 57 *57 4 |
| 1589 58 4 | 7 189 6 | 3 2 18 |
| 18 7 2 | 3 5 4 | 9 18 6 |
+-------------------+-------------------+-------------------+
| 78 38 6 | 5 379 2 | 4 18 189 |
| 578 2 1 | 4 36 79 | 57 36 89 |
| 4 35 9 | 1 *67 8 | 2 *67 35 |
+-------------------+-------------------+-------------------+
| 2 1 5 | 8 4 3 | 6 9 7 |
| 6 4 7 | 9 12 15 | 8 3-5 235 |
| 3 9 8 | 6 *27 57 | 1 4 *25 |
+-------------------+-------------------+-------------------+
r1c8+r6c58+r9c59 can't be [77622] => r8c8 can't be 5
On the other hand, I don't like chains so this might be how I crack it...
There is also a very short forcing chain (darn near an XY-wing ... maybe it is a wing of some sort -- I am unsure as I haven't really learned the more advanced wings) that cracks it to singletons (assuming I grabbed the right PM's as a starting point):
- Code: Select all
189 6 3 | 2 189 19 | 57 57 4
1589 58 4 | 7 189 6 | 3 2 18
18 7 2 | 3 5 4 | 9 18 6
----------+----------+----------
78 38 6 | 5 379 2 | 4 18 189
578 2 1 | 4 36 79 | 57 36 89
4 35 9 | 1 67 8 | 2 67 35
----------+----------+----------
2 1 5 | 8 4 3 | 6 9 7
6 4 7 | 9 12 15 | 8 35 235
3 9 8 | 6 27 57 | 1 4 25
r5c6=7 r5c7=5 + r9c6=7 r9c9=5 ==> r6c9<>5
Cheers...
- drac
[edit: removed spurrious reference to c9]
