Another one has me stumped

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Another one has me stumped

Postby I Am Bruce » Thu Feb 28, 2008 7:08 am

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?

Thanks in advance.
I Am Bruce
 
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Joined: 04 February 2008

Postby daj95376 » Thu Feb 28, 2008 9:02 am

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
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Thanks, but

Postby I Am Bruce » Thu Feb 28, 2008 1:18 pm

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.
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Joined: 04 February 2008

Postby Pat » Thu Feb 28, 2008 2:30 pm

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
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This is the original

Postby I Am Bruce » Thu Feb 28, 2008 3:12 pm

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

Postby Pat » Thu Feb 28, 2008 4:03 pm

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,
your supposed answer is wrong !
    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
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Postby I Am Bruce » Fri Feb 29, 2008 3:13 am

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

Postby Jean-Christophe » Fri Feb 29, 2008 9:04 am

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.
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Joined: 22 January 2006


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