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Low Rated Menneske

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Wed Aug 27, 2008 10:28 pm    Post subject: Low Rated Menneske Reply with quote

I'm back!

(Africa was wonderful! Three weeks without the internet, radio, TV, or newspapers. Mostly by choice.)

I tried to solve this one on the plane flight home.
Code:
Puzzle: M1748418vh
+-------+-------+-------+
| 7 2 . | . . 6 | . . . |
| . . . | 4 . . | 8 . . |
| . . 3 | . . . | . . . |
+-------+-------+-------+
| . . 7 | . . . | . . 6 |
| . . 9 | . 2 . | . . 5 |
| 6 . . | . 5 4 | . . . |
+-------+-------+-------+
| 9 . 6 | . . 1 | . 3 . |
| 1 7 . | . 9 . | 2 . . |
| . . . | 7 . . | 1 . . |
+-------+-------+-------+

After much more than basics, I am up to here:
Quote:
+----------------+----------------+----------------+
| 7 2 48 | 1358 138 6 | 49 459 349 |
| 5 6 1 | 4 37 9 | 8 27 23 |
| 48 9 3 | 58 78 2 | 6 457 1 |
+----------------+----------------+----------------+
| 23 5 7 | 1389 138 38 | 49 1249 6 |
| 48 14 9 | 6 2 7 | 3 18 5 |
| 6 13 28 | 139 5 4 | 7 1289 289 |
+----------------+----------------+----------------+
| 9 8 6 | 2 4 1 | 5 3 7 |
| 1 7 45 | 38 9 358 | 2 6 48 |
| 23 34 245 | 7 6 58 | 1 489 489 |
+----------------+----------------+----------------+

Keith
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Thu Aug 28, 2008 1:47 am    Post subject: Reply with quote

not looking at the white area... these are my first few steps. these steps do not complete it. Cool

Code:
.---------------------.---------------------.---------------------.
| 7      2      48    | 13589  138    6     | 349    1459   1349  |
| 5      6      1     | 4      37     239   | 8      279    239   |
| 48     9      3     | 158    178    258   | 6      12457  124   |
:---------------------+---------------------+---------------------:
| 2348   5      7     | 1389   138    389   | 349    12489  6     |
| 348    134    9     | 6      2      7     | 34     148    5     |
| 6      13     28    | 1389   5      4     | 7      1289   12389 |
:---------------------+---------------------+---------------------:
| 9      8      6     | 2      4      1     | 5      3      7     |
| 1      7      45    | 358    9      358   | 2      6      48    |
| 234    34     245   | 7      6      58    | 1      489    489   |
'---------------------'---------------------'---------------------'


I think most would find the xyz-wing
coloring on 4
edit:

I made a blunder here. sorry about that.


Last edited by storm_norm on Thu Aug 28, 2008 8:31 pm; edited 1 time in total
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Thu Aug 28, 2008 1:49 am    Post subject: Reply with quote

Hi Keith, welcome back. Glad you enjoyed your technology-free vacation.

This was an interesting puzzle, just as challenging as many of the Super Hards. For me, it took three ERs, a Finned X-Wing and breaking up a DP on an almost Type 6.
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.

PostPosted: Thu Aug 28, 2008 2:52 am    Post subject: Re: Low Rated Menneske Reply with quote

keith wrote:
I'm back!

(Africa was wonderful! Three weeks without the internet, radio, TV, or newspapers. Mostly by choice.)

Keith


There is no chance I would accept that, happy for you that you can!
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Thu Aug 28, 2008 2:16 pm    Post subject: Reply with quote

storm_norm wrote:
... the extended w-wing marked below ...
removes the 8 in r6c9
I cant see that. The pairs 48 in r1c3 and r8c9 are only a "half m-wing" with the strong link for 4 in row 8. I.e. from r8c9=8 follows r1c3=8, but not r8c9=4 => r1c3=4.

This is a cumbersome puzzle.
skyscraper 9, kite 4, xyz-wing 134, xy-wing 238 brought me here:
Code:
 *-------------------------------------------------*
 | 7   2   48   | 1358  138  6    |#49 #459   349  |
 | 5   6   1    | 4     37   9    | 8   27    23   |
 | 48  9   3    | 58    78   2    | 6   457   1    |
 |--------------+-----------------+----------------|
 | 23  5   7    | 189   138  38   |#49 #1249  6    |
 | 48  14  9    | 6     2    7    | 3   18    5    |
 | 6   13  28   | 139   5    4    | 7   1289  289  |
 |--------------+-----------------+----------------|
 | 9   8   6    | 2     4    1    | 5   3     7    |
 | 1   7  @45   | 38    9   @358  | 2   6    @48   |
 | 23  34 @245  | 7     6   @58   | 1   489  @489  |
 *-------------------------------------------------*

Then two uniqueness eliminations, which did not help much:
UR 49 in r14c78, strong link 4 in r4, r1c8<>9
DP 45-58-48 in r89c369, x-wing 5, strong link 4 in r8, r9c9<>4
[Edit:]Corrected the typo.
Code:
 *-------------------------------------------------*
 | 7   2   48   | 1358  138  6    | 49  45    349  |
 | 5   6   1    | 4    #37   9    | 8   27   *23   |
 |*48  9   3    | 58   #78   2    | 6   457   1    |
 |--------------+-----------------+----------------|
 | 23  5   7    | 189   138  38   | 49  1249  6    |
 |*48  14  9    | 6     2    7    | 3   18    5    |
 | 6   13 *28   | 139   5    4    | 7   1289 -289  |
 |--------------+-----------------+----------------|
 | 9   8   6    | 2     4    1    | 5   3     7    |
 | 1   7   45   | 38    9    358  | 2   6     48   |
 | 23  34  245  | 7     6    58   | 1   489   89   |
 *-------------------------------------------------*

When searching for generalized xy-wings i finally found this 6-cell xy-chain:
One of r2c5=3 and r3c5=8 must be true:
r2c5=3 => r2c9=2
r3c5=8 => r3c1=4 => r5c1=8 => r6c3=2
r6c9<>2

After that still a UR and xy-wing was needed.


Last edited by ravel on Fri Aug 29, 2008 8:45 am; edited 1 time in total
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Thu Aug 28, 2008 4:53 pm    Post subject: Reply with quote

The best I can find involves an XY-Chain and a UR.

Code:
 Where Keith's (valiant) initial effort stops
 +--------------------------------------------------------------+
 |  7     2     48    |  1358  138   6     |  49    459   349   |
 |  5     6     1     |  4     37    9     |  8     27    23    |
 |  48    9     3     |  58    78    2     |  6     457   1     |
 |--------------------+--------------------+--------------------|
 |  23    5     7     |  1389  138   38    |  49    1249  6     |
 |  48    14    9     |  6     2     7     |  3     18    5     |
 |  6     13    28    |  139   5     4     |  7     1289  289   |
 |--------------------+--------------------+--------------------|
 |  9     8     6     |  2     4     1     |  5     3     7     |
 |  1     7     45    |  38    9     358   |  2     6     48    |
 |  23    34    245   |  7     6     58    |  1     489   489   |
 +--------------------------------------------------------------+
 # 56 eliminations remain

 -5r8c3  4r8c3  3r9c2  2r9c1  3r4c1  8r4c6  5r9c6  [XY-Chain] <> 5 [r8c6],[r9c3]

Code:
 +--------------------------------------------------------------+
 |  7     2     48    |  1358  138   6     |  49    459   39    |
 |  5     6     1     |  4     37    9     |  8     27    23    |
 |  48    9     3     |  58    78    2     |  6     457   1     |
 |--------------------+--------------------+--------------------|
 |  23    5     7     |  1389  138   38    |  49    1249  6     |
 |  48    14    9     |  6     2     7     |  3    *18    5     |
 |  6     13   *28    |  139   5     4     |  7     89+12 89+2  |
 |--------------------+--------------------+--------------------|
 |  9     8     6     |  2     4     1     |  5     3     7     |
 |  1     7     5     |  38    9     38    |  2     6     4     |
 |  23    34    24    |  7     6     5     |  1     89    89    |
 +--------------------------------------------------------------+
 # 48 eliminations remain

    (38) UR Type 1 [r48c46]              <> 38   [r4c4]   IGNORE!
    (89) UR Type ? [r69c89]              <>  8   [r6c89]

Note to Keith: Remember all of the trouble I had (in the Players' Forums) learning the DP pattern in a basic UR? I bet you thought that I'd never learn to spot any kind of UR. Well, you'd still be mostly right. Laughing
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Thu Aug 28, 2008 8:30 pm    Post subject: Reply with quote

Quote:
I cant see that. The pairs 48 in r1c3 and r8c9 are only a "half m-wing" with the strong link for 4 in row 8. I.e. from r8c9=8 follows r1c3=8, but not r8c9=4 => r1c3=4.


wow, you are right, total blunders on my part.
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Thu Aug 28, 2008 8:31 pm    Post subject: Reply with quote

daj95376 wrote:
(89) UR Type ? [r69c89] <> 8 [r6c89]
Nice catch aagain. Dont know a type either. Maybe aligned pair UR ?
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Thu Aug 28, 2008 9:05 pm    Post subject: Reply with quote

ravel wrote:


This is a cumbersome puzzle.
skyscraper 9, kite 4, xyz-wing 134, xy-wing 238 brought me here:
Code:
 *-------------------------------------------------*
 | 7   2   48   | 1358  138  6    |#49 #459   349  |
 | 5   6   1    | 4     37   9    | 8   27    23   |
 | 48  9   3    | 58    78   2    | 6   457   1    |
 |--------------+-----------------+----------------|
 | 23  5   7    | 189   138  38   |#49 #1249  6    |
 | 48  14  9    | 6     2    7    | 3   18    5    |
 | 6   13  28   | 139   5    4    | 7   1289  289  |
 |--------------+-----------------+----------------|
 | 9   8   6    | 2     4    1    | 5   3     7    |
 | 1   7  @45   | 38    9   @358  | 2   6    @48   |
 | 23  34 @245  | 7     6   @58   | 1   489  @489  |
 *-------------------------------------------------*


I had a very similar sequence of eliminations. I noticed a finned x-wing destructively interacting with the skyscraper on <9> and took the eliminations from both, followed by a finned x-wing on <4> instead of the kite, then the xyz-wing <134> and the xy-wing <238>. At that point, my grid was identical to the posted grid except I had an additional <3> digit in r4c4. This condition in fact then offered a diagonal UR on <38> like a Type 3 with a strong link on <3> in col6 & row8 that deleted the <3> from r4c4 thereby matching the posted grid. I saw the UR on <49>, but missed the DP 45-58-48 in r89c369.

As I have previously commented, I am having a mental block with these MUG/DP conditions and in this case I am not able to follow the logic that removes <9> from r9c9.

Could someone please provide some details.

Thanks in advance .......

Ravel, I really admired the xy-chain to essentially finish off this puzzle.

Ted Question
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Thu Aug 28, 2008 9:25 pm    Post subject: Reply with quote

daj95376 wrote:
The best I can find involves an XY-Chain and a UR.

Code:
 +--------------------------------------------------------------+
 |  7     2     48    |  1358  138   6     |  49    459   39    |
 |  5     6     1     |  4     37    9     |  8     27    23    |
 |  48    9     3     |  58    78    2     |  6     457   1     |
 |--------------------+--------------------+--------------------|
 |  23    5     7     |  1389  138   38    |  49    1249  6     |
 |  48    14    9     |  6     2     7     |  3    *18    5     |
 |  6     13   *28    |  139   5     4     |  7     89+12 89+2  |
 |--------------------+--------------------+--------------------|
 |  9     8     6     |  2     4     1     |  5     3     7     |
 |  1     7     5     |  38    9     38    |  2     6     4     |
 |  23    34    24    |  7     6     5     |  1     89    89    |
 +--------------------------------------------------------------+
 # 48 eliminations remain

    (38) UR Type 1 [r48c46]              <> 38   [r4c4]   IGNORE!
    (89) UR Type ? [r69c89]              <>  8   [r6c89]


If the <89> UR is treated as a normal Type 3 (by forgetting about the strong links), then the pseudo-cell <12> in box6 acts as the pivot for a xy-wing <128> that deletes <8> from r5c1 thereby finishing off the puzzle. The Type issue is then NOT an issue.

Ted
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Thu Aug 28, 2008 9:36 pm    Post subject: Reply with quote

Ted,

Ravel mis-typed. It should be: r9c9<>4. r8c9 is either 4 or 8. If 8, then the 5 X-Wing collapses removing the 2 and 3 "extra" digits and leaving the 9 in r9c9 as the only way to avoid the DP. So either way, r9c9 is not 4.

I agree that the 89 UR is an XY-Wing equivalent, which is interesting.
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Thu Aug 28, 2008 9:39 pm    Post subject: Reply with quote

From the same place as daj95376, I went right to Medusa:
Code:

+----------------+-----------------+----------------+
| 7    2    4a8A | 1358  138  6    | 49  459   349  |
| 5    6    1    | 4     37   9    | 8   27    23   |
|@4a8A 9    3    |#5-8   78   2    | 6   4A57  1    |
+----------------+-----------------+----------------+
| 23   5    7    | 1389  138  38   | 49  12a49 6    |
| 4A8a 1A4a 9    | 6     2    7    | 3   1a8A  5    |
| 6    1a3A 2a8A |@13a9  5    4    | 7   1289  289  |
+----------------+-----------------+----------------+
| 9    8    6    | 2     4    1    | 5   3     7    |
| 1    7    45   |@38(a) 9    358  | 2   6     48   |
| 2a3A 3a4A 2A45 | 7     6    58   | 1   489   489  |
+----------------+-----------------+----------------+

The 3a at r6c4 is easily "transported" (or simply multi-colored) to 8a at r8c4, trapping <8> at r3c4.

This leads immediately to a "wrap":
Code:

+----------------+-----------------+----------------+
| 7    2    4a8A | 1358  138  6    | 49  459   349  |
| 5    6    1    | 4     3A7a 9    | 8  #2a7A  23   |
| 4a8A 9    3    | 5     7A8a 2    | 6   4A7a  1    |
+----------------+-----------------+----------------+
| 23   5    7    | 1389  138  38   | 49 #12a49 6    |
| 4A8a 1A4a 9    | 6     2    7    | 3   1a8A  5    |
| 6    1a3A 2a8A | 13a9  5    4    | 7   1289  289  |
+----------------+-----------------+----------------+
| 9    8    6    | 2     4    1    | 5   3     7    |
| 1    7    45   | 38    9    358  | 2   6     48   |
| 2a3A 3a4A 2A45 | 7     6    58   | 1   489   489  |
+----------------+-----------------+----------------+

There are two 2a's in c8, so all the "a" values are false, solving the puzzle quite easily.
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Thu Aug 28, 2008 10:08 pm    Post subject: Reply with quote

Thanks Asellus. I went back and reviewed Ravel's original input, and it is now obvious by looking at the resultant code that a typo occurred; I should have noticed that originally.

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Thu Aug 28, 2008 10:23 pm    Post subject: Reply with quote

tlanglet wrote:
... the pseudo-cell <12> in box6 acts as the pivot for a xy-wing <128> that deletes <8> from r5c1 ...

I like it Exclamation _____ I keep forgetting that a pair of UR cells can often be treated as a pseudo-cell.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Thu Aug 28, 2008 10:41 pm    Post subject: Reply with quote

tlanglet wrote:
daj95376 wrote:
The best I can find involves an XY-Chain and a UR.

Code:
 +--------------------------------------------------------------+
 |  7     2     48    |  1358  138   6     |  49    459   39    |
 |  5     6     1     |  4     37    9     |  8     27    23    |
 |  48    9     3     |  58    78    2     |  6     457   1     |
 |--------------------+--------------------+--------------------|
 |  23    5     7     |  1389  138   38    |  49    1249  6     |
 |  48    14    9     |  6     2     7     |  3    *18    5     |
 |  6     13   *28    |  139   5     4     |  7     89+12 89+2  |
 |--------------------+--------------------+--------------------|
 |  9     8     6     |  2     4     1     |  5     3     7     |
 |  1     7     5     |  38    9     38    |  2     6     4     |
 |  23    34    24    |  7     6     5     |  1     89    89    |
 +--------------------------------------------------------------+
 # 48 eliminations remain

    (38) UR Type 1 [r48c46]              <> 38   [r4c4]   IGNORE!
    (89) UR Type ? [r69c89]              <>  8   [r6c89]


If the <89> UR is treated as a normal Type 3 (by forgetting about the strong links), then the pseudo-cell <12> in box6 acts as the pivot for a xy-wing <128> that deletes <8> from r5c1 thereby finishing off the puzzle. The Type issue is then NOT an issue.

Ted

Wow! I am impressed!

Is it correct to say that it also eliminates <8> in R6C89, the UR cells in R6?

Keith
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Thu Aug 28, 2008 10:48 pm    Post subject: Reply with quote

daj95376 wrote:
Note to Keith: Remember all of the trouble I had (in the Players' Forums) learning the DP pattern in a basic UR? I bet you thought that I'd never learn to spot any kind of UR. Well, you'd still be mostly right. Laughing

Danny,

That is not my recollection. I do remember you asking some challenging questions that forced me to reconsider and revise my explanations ...

Keith
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tlanglet



Joined: 17 Oct 2007
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Location: Northern California Foothills

PostPosted: Thu Aug 28, 2008 11:55 pm    Post subject: Reply with quote

keith wrote:


Is it correct to say that it also eliminates <8> in R6C89, the UR cells in R6?

Keith


I saw the deletions of <8> in box6 but did not mention them since I am not sure if they are valid. I assume they are based on a comment by a person named "Keith" who once noted that interactions of solutions do not invalidate the separate solutions.

Ted
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Aug 29, 2008 2:44 am    Post subject: Reply with quote

Quote:
If the <89> UR is treated as a normal Type 3 (by forgetting about the strong links), then the pseudo-cell <12> in box6 acts as the pivot for a xy-wing <128> that deletes <8> from r5c1 thereby finishing off the puzzle. The Type issue is then NOT an issue.


that's impressive enough to use on a geeky date Exclamation
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Fri Aug 29, 2008 8:43 am    Post subject: Reply with quote

tlanglet wrote:
I am not able to follow the logic that removes <9> from r9c9.
I am very sorry about this typo (thanks to Asellus to clarify that). I do know the troubles you can have, if you believe a typo.


Concerning Danny's xy UR: A simple way to understand it was often used in this forum. Since one of the extra candidates must be true, look, what it implies, i.e. (in sudoku terms) try a (multiple) forcing chain. In this case one of
r6c8=1 => r5c8=8
r6c89=2 => r6c3=8
must be true.

We have seen many of similar, often more complex deductions here, especially by Johan.

Anyway this special pattern has its own charm.
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Fri Aug 29, 2008 5:45 pm    Post subject: Reply with quote

I used two ER’s, a skyscraper, an xyz-wing , an xy-wing, colouring on <4>, a diagonal variant of a Type 4 UR (Type 6??), and one of them funny UR’s on <38> that Nataraj recently referred to as weasels. But still can’t solve it . I guess it needs xy-chains and stuff that ain't in my arsenal.
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