Another one has me stumped

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Another one has me stumped

Thanks for pointing out my oversight in the last one that I needed help on. ... Now here is another. I don't think I overlooked any of the easy stuff

Code: Select all
`*----------------------------------------------------------*  | 8     7     4     | 9     3     6     | 5     1     2     |  | 16    5     2     | 8     147   147   | 679   479   @     |  | 9     3     16    | 15    1457  2     | 67    47    8     |  |------------------+------------------+------------------|  | 2     4     19    | 7     6     16    | 3     8     5     |  | 57    6     8     | 3     2     459   | 1     79    479   |  | 3     19    57    | 15    1459  8     | 2     6     479   |  |------------------+------------------+------------------|  | 67    2     679   | 4     8     3     | 79    5     1     |  | 157   8     1579  | 2     179   179   | 4     3     6     |  | 4     19    3     | 6     1579  1579  | 8     2     79    |  *--------------------------------------------------------*`

My suspicion is that if I get over the current hurdle, the rest will fall into place quite easily. What trick have I overlooked?

I Am Bruce

Posts: 11
Joined: 04 February 2008

Code: Select all
`+-----------------------+| 8 7 4 | 9 3 6 | 5 1 2 || . 5 2 | 8 . . | . . . || 9 3 . | . . 2 | . . 8 ||-------+-------+-------|| 2 4 . | 7 6 . | 3 8 5 || . 6 8 | 3 2 . | 1 . . || 3 . . | . . 8 | 2 6 . ||-------+-------+-------|| . 2 . | 4 8 3 | . 5 1 || . 8 . | 2 . . | 4 3 6 || 4 . 3 | 6 . . | 8 2 . |+-----------------------+`

At first, I thought the (@) character was the source of your trouble. It wasn't. It's possible that you incorrectly placed 5 in [r2c2].

Code: Select all
`+-----------------------+| 8 7 4 | 9 3 6 | 5 1 2 || . . 2 | 8 . . | . . 3 || 9 3 . | . . 2 | . . 8 ||-------+-------+-------|| 2 4 . | 7 6 . | 3 8 5 || . 6 8 | 3 2 . | 1 . . || 3 . . | . . 8 | 2 6 . ||-------+-------+-------|| . 2 . | 4 8 3 | . 5 1 || . 8 . | 2 . . | 4 3 6 || 4 . 3 | 6 . . | 8 2 . |+-----------------------+`
daj95376
2014 Supporter

Posts: 2624
Joined: 15 May 2006

Thanks, but

Thanks for the thoughts, but the 5 at r2c2 is a given.

I did, however, discover that r9c6 should have been a 5, which is a given.

Also, my apologies for the @ at r2c9. It should have been a 3.

By correcting the 5 at r9c6, I solved r5c1 r6c3 and r8c3. But that's when it ended.
I Am Bruce

Posts: 11
Joined: 04 February 2008

I Am Bruce wrote:Thanks for the thoughts, but the 5 at r2c2 is a given.

I did, however, discover that r9c6 should have been a 5, which is a given.

Also, my apologies for the @ at r2c9. It should have been a 3.

that's all fine but you have some other error in the posted puzzle,
as it is r2c2 cannot be 5
it would help a lot if you post the original puzzle

Pat

Posts: 3506
Joined: 18 July 2005

This is the original

This is the original puzzle as presented to me:

Code: Select all
`+-----------------------+ | . 7 4 | 9 . 6 | 5 . . | | . 5 2 | . . . | . . . | | 9 . . | . . 2 | . . . | |-------+-------+-------| | . 4 . | 7 . . | . . 5 | | . . 8 | . . . | 1 . . | | 3 . . | . . 8 | . 6 . | |-------+-------+-------| | . . . | 4 . . | . . 1 | | . . . | . . . | 4 3 . | | . . 3 | 6 . 5 | 8 2 . | +-----------------------+`

Through brute force (guessing on one of the pairs), I solved it as follows:

Code: Select all
`+-----------------------+ | 8 7 4 | 9 3 6 | 5 1 2 | | 6 5 2 | 8 4 1 | 7 9 3 | | 9 3 1 | 5 7 2 | 6 4 8 | |-------+-------+-------| | 2 4 9 | 7 6 1 | 3 8 5 | | 5 6 8 | 3 2 4 | 1 7 9 | | 3 1 7 | 5 9 8 | 2 6 1 | |-------+-------+-------| | 7 2 6 | 4 8 3 | 9 5 1 | | 1 8 5 | 2 9 7 | 4 3 6 | | 4 9 3 | 6 1 5 | 8 2 7 | +-----------------------+`

I know there is a right way to solve it and I'd sure like to know it.

And, again, thanks for all of your help.
I Am Bruce

Posts: 11
Joined: 04 February 2008

I Am Bruce wrote:This is the original puzzle as presented to me:

Code: Select all
`+-----------------------+ | . 7 4 | 9 . 6 | 5 . . | | . 5 2 | . . . | . . . | | 9 . . | . . 2 | . . . | |-------+-------+-------| | . 4 . | 7 . . | . . 5 | | . . 8 | . . . | 1 . . | | 3 . . | . . 8 | . 6 . | |-------+-------+-------| | . . . | 4 . . | . . 1 | | . . . | . . . | 4 3 . | | . . 3 | 6 . 5 | 8 2 . | +-----------------------+`

Through brute force (guessing on one of the pairs), I solved it as follows:

Code: Select all
`+-----------------------+ | 8 7 4 | 9 3 6 | 5 1 2 | | 6 5 2 | 8 4 1 | 7 9 3 | | 9 3 1 | 5 7 2 | 6 4 8 | |-------+-------+-------| | 2 4 9 | 7 6 1 | 3 8 5 | | 5 6 8 | 3 2 4 | 1 7 9 | | 3 1 7 | 5 9 8 | 2 6 1 | |-------+-------+-------| | 7 2 6 | 4 8 3 | 9 5 1 | | 1 8 5 | 2 9 7 | 4 3 6 | | 4 9 3 | 6 1 5 | 8 2 7 | +-----------------------+`

I know there is a right way to solve it and I'd sure like to know it.

And, again, thanks for all of your help.

even with brute force,
e.g. in column 4 you have no 1,
in column 5 you have no 5,
in column 6 you have no 9

it's a tough puzzle which will eventually be solved with an xy-wing
-- suppose you show us how far you get without guessing,
and we'll take it up from there

Pat

Posts: 3506
Joined: 18 July 2005

I am having lots of trouble with this one. I can't even "cheat" a right answer. Sorry.

I posted the source earlier and here is what I've got so far:

Code: Select all
`*----------------------------------------------------------*  | 8     7     4     | 9     3     6     | 5     1     2     |  | 16    5     2     | 8     147   147   | 679   479   3     |  | 9     3     16    | 15    1457  2     | 67    47    8     |  |------------------+------------------+------------------|  | 2     4     19    | 7     6     19    | 3     8     5     |  | 5     6     8     | 3     2     49    | 1     79    479   |  | 3     19    7     | 15    1459  8     | 2     6     49    |  |------------------+------------------+------------------|  | 67    2     69    | 4     8     3     | 79    5     1     |  | 17    8     5     | 2     179   179   | 4     3     6     |  | 4     19    3     | 6     179   5     | 8     2     79    |  *--------------------------------------------------------* `
I Am Bruce

Posts: 11
Joined: 04 February 2008

Maybe daj95376 comment wasn't clear enough.
This state is indeed invalid, no solution.
You should restart from scratch.
FYI the following cells are wrong in this state: r4c1, r4c5, r5c2, r5c5, r7c2
The original grid is OK with a unique solution.
Jean-Christophe

Posts: 149
Joined: 22 January 2006