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VH+ by TTSieh (game 0046)

 
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ravel



Joined: 21 Apr 2006
Posts: 536
PostPosted: Mon Aug 18, 2008 3:39 pm    Post subject: VH+ by TTSieh (game 0046) Reply with quote
Code:
 +-------+-------+-------+
 | . . 1 | 2 . . | . . . |
 | . 3 . | . . 4 | 5 . . |
 | 6 . . | . . . | . 7 . |
 +-------+-------+-------+
 | 5 . . | 7 . . | . 2 . |
 | . . . | . 8 . | . . . |
 | . 4 . | . . . | . . 6 |
 +-------+-------+-------+
 | . 6 . | . . . | . . 4 |
 | . . 8 | 9 . . | . 1 . |
 | . . . | . . 3 | 9 . 5 |
 +-------+-------+-------+ TTHsieh
>>> play online
Many techniques.
Again you can get started with coloring (hint: in 4).
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Tue Aug 19, 2008 1:31 am    Post subject: Reply with quote
Quote:
Many techniques.

This is embarrassing, but what the heck, it's not the first time. After filling in the pencil marks there are only two bivalue cells, a zillion cells with a zillion candidates and I can't eliminate even one candidate. I saw no subsets, no locked candidates and couldn't see how to use the hint. A pretty sorry state of affairs. Crying or Very sad
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
PostPosted: Tue Aug 19, 2008 2:50 am    Post subject: Reply with quote
Well, I solved it by a longish route and not the prettiest.

[1] Finned Swordfish c148 r9c3<>4
[2] Sashimi X-Wing r28 (or ER) r3c2<>2
[3] 35 UR r36c45, r3c5<>3
[4] Turbot Fish (or coloring or ER) r5c3<>7
[5] A chain of 2 XYs and then two strong links, one grouped:
(3=8)r1c7 - (8=7)r1c1 - (7)r56c1=(7)r5c2 - (7)r5c7=(7)r6c7; r6c7<>3
And, finally...
[6] An ALS chain with a grouped weak link:
(9=7)r5c2 - (7={13})r5c79 - ({13}=8)r4c9 - (8=9)r4c2; r13c2|r45c3<>9

Note: This last chain is actually a loop, so all of the links become conjugate. I didn't notice that at the time. But, the <9> eliminations solve the puzzle in any case.
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
PostPosted: Tue Aug 19, 2008 2:54 am    Post subject: Reply with quote
Try a finned swordfish on 4s.

I don't know what that would be in colors?

Two w-wings but otherwise patterns I like, and in fact I like w-wings! Smile

Nice puzzle, although the start is pretty awful. Crying or Very sad
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ravel



Joined: 21 Apr 2006
Posts: 536
PostPosted: Tue Aug 19, 2008 7:48 am    Post subject: Reply with quote
Marty R. wrote:
...couldn't see how to use the hint.
Marty,

try to "color" the pincers of "useless" skyscrapers.

If i made no mistake, no other chains were needed, but 5 or 6 techniques including a well known one, which i rarely use.
[Added:] i missed something the first time, so these are the techniques i used now (in other order):
xy-wing, w-wing, 2 skyscrapers, 2 kites, 2 UR s (type 3 and 4), and the 3 strong links at the beginning
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Tue Aug 19, 2008 3:55 pm    Post subject: Reply with quote
This is the mess I'm in. I previously tried coloring skyscrapers but didn't see anything.

Code:

+-------------------+-------------------+-------------------+
| 4789   5789 1     | 2     35679 56789 | 3468  34689 389   |
| 2789   3    279   | 168   1679  4     | 5     689   1289  |
| 6      2589 2459  | 1358  1359  1589  | 12348 7     12389 |
+-------------------+-------------------+-------------------+
| 5      189  369   | 7     13469 169   | 1348  2     1389  |
| 12379  1279 23679 | 13456 8     12569 | 1347  3459  1379  |
| 123789 4    2379  | 135   12359 1259  | 1378  3589  6     |
+-------------------+-------------------+-------------------+
| 12379  6    23579 | 158   1257  12578 | 2378  38    4     |
| 2347   257  8     | 9     24567 2567  | 2367  1     237   |
| 1247   127  247   | 1468  12467 3     | 9     68    5     |
+-------------------+-------------------+-------------------+

Play this puzzle online at the Daily Sudoku site
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ravel



Joined: 21 Apr 2006
Posts: 536
PostPosted: Tue Aug 19, 2008 4:42 pm    Post subject: Reply with quote
There are two, skyscraper in columns or rows.
Code:
+--------------------+-------------------+--------------------+
|-4789   5789  1     | 2     35679 56789 | 3468  @34689 389   |
| 2789   3     279   | 168   1679  4     | 5      689   1289  |
| 6      2589 #2459  | 1358  1359  1589  | 123-48 7     12389 |
+--------------------+-------------------+--------------------+
| 5      189   369   | 7     13469 169   | 1348   2     1389  |
| 12379  1279  23679 |#13456 8     12569 | 1347  @3459  1379  |
| 123789 4     2379  | 135   12359 1259  | 1378   3589  6     |
+--------------------+-------------------+--------------------+
| 12379  6     23579 | 158   1257  12578 | 2378   38    4     |
| 2347   257   8     | 9     24567 2567  | 2367   1     237   |
| 1247   127  #247   |#1468  12467 3     | 9      68    5     |
+--------------------+-------------------+--------------------+
+--------------------+-------------------+-------------------+
|-4789   5789  1     | 2     35679 56789 | 3468  34689 389   |
| 2789   3     279   | 168   1679  4     | 5     689   1289  |
| 6      2589 #2459  | 1358  1359  1589  |#12348 7     12389 |
+--------------------+-------------------+-------------------+
| 5      189   369   | 7    #13469 169   |#1348  2     1389  |
| 12379  1279  23679 | 13456 8     12569 | 1347  3459  1379  |
| 123789 4     2379  | 135   12359 1259  | 1378  3589  6     |
+--------------------+-------------------+-------------------+
| 12379  6     23579 | 158   1257  12578 | 2378  38    4     |
|@2347   257   8     | 9    @24567 2567  | 2367  1     237   |
| 1247   127   2-47  | 1468  12467 3     | 9     68    5     |
+--------------------+-------------------+-------------------+

You can see, that the 4 in r3c3 has 3 strong links. So if its not true, all 3 others have to be true. [eh Edit, wanted to say:]It is often worth to check, if this is possible.
Here you soon get a contradiction:
Code:
+--------------------+-------------------+-------------------+
|^4789   5789  1     | 2     35679 56789 | 3468 @34689 389   |
| 2789   3     279   | 168   1679  4     | 5     689   1289  |
| 6      2589  2459  | 1358  1359  1589  |#12348 7     12389 |
+--------------------+-------------------+-------------------+
| 5      189   369   | 7    #13469 169   |@1348  2     1389  |
| 12379  1279  23679 |@13456 8     12569 | 1347 #3459  1379  |
| 123789 4     2379  | 135   12359 1259  | 1378  3589  6     |
+--------------------+-------------------+-------------------+
| 12379  6     23579 | 158   1257  12578 | 2378  38    4     |
| 2347   257   8     | 9    @24567 2567  | 2367  1     237   |
| 1247   127  @247   |#1468  12467 3     | 9     68    5     |
+--------------------+-------------------+-------------------+
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ravel



Joined: 21 Apr 2006
Posts: 536
PostPosted: Mon Aug 25, 2008 10:43 am    Post subject: Reply with quote
This is the rest of my solution.
After the step above and kites 2 and 7:
A rare UR type 3 (35), the extra candidates 129 form a quad 1279 with r279c5
(As a type 6 also 3 can be eliminated from r3c5)
Code:
 *--------------------------------------------------------*
 | 78    5789  1     | 2  356-7-9 6789  | 38    4  389    |
 | 278   3     279   | 18 *179    4     | 5     6  189    |
 | 6     589   4     |#35 #1359   189   | 1238  7  12389  |
 |-------------------+------------------+-----------------|
 | 5     89    369   | 7  -136-9  169   | 4     2  138    |
 | 127   279   2369  | 4   8      1269  | 137   5  137    |
 | 1278  4     237   |#35 #1235   12    | 1378  9  6      |
 |-------------------+------------------+-----------------|
 | 9     6     5     | 18 *127    1278  | 27    3  4      |
 | 3     27    8     | 9   4      5     | 6     1  27     |
 | 4     1     27    | 6  *27     3     | 9     8  5      |
 *--------------------------------------------------------*

skyscraper 1, xy-wing 256 (also was xyz-wing), skyscraper 8 follow
UR type 4 (59). Note the 9 in r1c5 was already eliminated above.
Code:
 *-----------------------------------------------*
 | 78  #57-9 1     | 2 #56   67    | 3   4  89   |
 | 278  3    279   | 1  79   4     | 5   6  89   |
 | 6   #59   4     | 3 #59   8     | 12  7  12   |
 |-----------------+---------------+-------------|
 | 5    8    369   | 7  36   169   | 4   2  13   |
 | 12   29   2369  | 4  8    1269  | 17  5  137  |
 | 127  4    237   | 5  123  12    | 8   9  6    |
 |-----------------+---------------+-------------|
 | 9    6    5     | 8  127  127   | 27  3  4    |
 | 3    27   8     | 9  4    5     | 6   1  27   |
 | 4    1    27    | 6  27   3     | 9   8  5    |
 *-----------------------------------------------*

A w-wing 27 finihes it off.
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