| View previous topic :: View next topic |
| Author |
Message |
mymega
Joined: 05 Sep 2006
Posts: 2
|
 Posted: Tue Sep 05, 2006 3:15 pm Post subject: Beginner |
 |
|
I am new to sudoku's, learning but still having trouble.
**1 *79 63*
*** *64 ***
6*9 1*8 475
**8 9** 74*
3** 48* **9
*94 *** 8**
973 841 **6
**2 653 **7
516 792 384
The hint option in this puzzle says to place the 7 in r5c6, I am just not seeing this move for some reason. I was trying to learn the x-wing but it does not seem to fit in this position? |
|
| Back to top |
|
 |
David Bryant
Joined: 29 Jul 2005
Posts: 559
Location: Denver, Colorado
|
| Posted: Tue Sep 05, 2006 6:44 pm Post subject: Notice the "hidden pairs" |
|
|
Hi, mymega! Welcome to the forum.
| Code: | **1 *79 63*
*** *64 ***
6*9 1*8 475
**8 9** 74*
3** 48* **9
*94 *** 8**
973 841 **6
**2 653 **7
516 792 384 |
The key to understanding the hint is a couple of "hidden pairs".
-- It appears that the only possibilities at r5c6 are {5, 6, 7}.
-- Now examine row 4. Both "5" and "6" lie in column 1, column 5, and column 9. So the only way those two values can fit into row 4 is at r4c2 & r4c6 -- we call this the "hidden pair" {5, 6} in r4c2 and r4c6.
-- Next, examine row 6. We can immediately rule out the possibility of either "5" or "6" at r6c5 and r6c9. Also, we can see that the "5" in the top center 3x3 box must lie in column 4 (at r1c4 or r2c4), so there can't be either a "5" or a "6" at r6c4, either. So the hidden pair {5, 6} must also lie in r6c6 and r6c8.
This leaves the "7" in r5c6, because it can't appear at r4c6 or r6c6. dcb |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
