Sudokus with an original rare shape

Everything about Sudoku that doesn't fit in one of the other sections

Re: The Easy Beauty

Postby udosuk » Mon Jul 24, 2006 6:02 pm

claudiarabia wrote:Here is another 21-clue Sudoku:
Code: Select all
4 . . . 1 . . . 9
. . . 2 . 3 . . .
. . 8 . . . 5 . .
. 2 . 1 . . . 3 .
. . . . 7 . . . .
. 6 . . . 5 . 8 .
. . 3 . . . 6 . .
. . . 8 . 2 . . .
5 . . . 4 . . . 1

I have to apply 2 chains to solve this puzzle:

After basic techniques:
Code: Select all
 4      3      567    |*57     1      8      | 2     *67     9   
 16    *1579   15679  | 2     -569    3      | 8      1467   467
 2      179    8      | 479    69     479    | 5      167    3   
----------------------+----------------------+-------------------
 79     2      4579   | 1      8      469    | 479    3      56 
 8     *159    1459   | 3      7      469    | 149   *56     2   
 3      6      1479   | 49     2      5      | 1479   8      47 
----------------------+----------------------+-------------------
 79     4      3      | 579    59     1      | 6      2      8   
 16     179    1679   | 8      3      2      | 47     4579   457
 5      8      2      | 6      4      79     | 3      79     1   

[r2c5]=5=[r1c4]-7-[r1c8]-6-[r5c8]-5-[r5c2]=5=[r2c2]-5-[r2c5], so r2c5<>5

And then after some moves incl. colouring/xy-wing/turbot fish:
Code: Select all
 4     3     67    | 5     1     8     | 2    *67    9   
 16    157   156   | 2     9     3     | 8     46   -467
 2     9     8     | 47    6     47    | 5     1     3   
-------------------+-------------------+-----------------
*79    2     4579  | 1     8     46    | 479   3     56 
 8    *15    1459  | 3     7     469   | 149  *56    2   
 3     6    *147   | 49    2     5     | 1479  8    *47 
-------------------+-------------------+-----------------
*79    4     3     | 79    5     1     | 6     2     8   
 16   *17    169   | 8     3     2     | 47    459   457
 5     8     2     | 6     4     79    | 3     79    1   

[r2c9]=7=[r1c8]-6-[r5c8]-5-[r5c2]-1-[r8c2]=7=[r7c1]=9=[r4c1]-7-[r6c3]-4-[r6c9]-7-[r2c9], so r2c9<>7

Then the puzzle is solved...

Any more elegant path please!?
udosuk
 
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Re: The Easy Beauty

Postby JPF » Mon Jul 24, 2006 10:25 pm

claudiarabia wrote:This is a real beauty worth do develop a more difficult pattern.
Thanks

claudiarabia wrote:Here is another 21-clue Sudoku:
Code: Select all
4 . . . 1 . . . 9
. . . 2 . 3 . . .
. . 8 . . . 5 . .
. 2 . 1 . . . 3 .
. . . . 7 . . . .
. 6 . . . 5 . 8 .
. . 3 . . . 6 . .
. . . 8 . 2 . . .
5 . . . 4 . . . 1

Claudia

to help udosuk:D , here is nearly the same, but very easy :

Code: Select all
 4 . . . 6 . . . 9
 . . . 2 . 3 . . .
 . . 9 . . . 5 . .
 . 2 . 1 . . . 3 .
 . . . . 7 . . . .
 . 6 . . . 5 . 8 .
 . . 3 . . . 6 . .
 . . . 8 . 2 . . .
 5 . . . 4 . . . 1


JPF
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Re: The Easy Beauty

Postby daj95376 » Tue Jul 25, 2006 2:33 am

udosuk wrote:Any more elegant path please!?

[Edited:] My solver produces two chains. The first may be simpler than yours. The second is comparable and I won't list it.

(20*) Hidden Single, Naked Pair, (3*) Locked Candidate (1), Hidden Single, Naked Quad, and Locked Candidate (1) gets me to:

Code: Select all
*--------------------------------------------------------------------*

| 4      3      567    | 57      1     8      | 2      67     9      |
| 16     1579   15679  | 2      569    3      | 8      1467   467    |
| 2      179    8      | 479    69     479    | 5      167    3      |
|----------------------+----------------------+----------------------|
| 79     2      4579   | 1      8      469    | 479    3      56     |
| 8      159    1459   | 3      7      469    | 149    56     2      |
| 3      6      1479   | 49     2      5      | 1479   8      47     |
|----------------------+----------------------+----------------------|
| 79     4      3      | 579    59     1      | 6      2      8      |
| 16     179    1679   | 8      3      2      | 47     4579   457    |
| 5      8      2      | 6      4      79     | 3      79     1      |
*--------------------------------------------------------------------*

At this point, there's a short chain

Code: Select all
[r1c4]=7 => [r1c8]=6 => { [r1c3]=5, [r5c8]=5 } => [b4]=INVALID => [r1c4]=5

followed by a Hidden Single, (2*) Naked Pair, XY-Wing, and (4*) Naked Single. Then a second chain is needed before a cascade of Singles.

[Edited:] It's possible to find a single chain solution because there's a backdoor single at [r1c8]=7 that can be resolved using just Naked/Hidden Singles. Unfortunately, my notation skills aren't adequate to show the path for [r1c8]=6 => [c7]=INVALID. [Edited:] I don't recommend using this chain in a solution, but it makes a nice FYI.
Last edited by daj95376 on Tue Jul 25, 2006 7:34 pm, edited 1 time in total.
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Re: The Easy Beauty

Postby gsf » Tue Jul 25, 2006 5:07 am

daj95376 wrote:FYI: There's a backdoor single at [r1c8]=7 for the grid above. Unfortunately, my notation skills aren't adequate to show the path of Naked/Hidden Singles for [r1c8]=6 => [c7]=INVALID.

there are 6 singles backdoors in bivalue cells
Code: Select all
[18]7[49]5[58]6[64]4[69]7[87]7
gsf
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Postby daj95376 » Tue Jul 25, 2006 5:53 am

[Edited: Discarded in favor of updating previous message.]
Last edited by daj95376 on Tue Jul 25, 2006 7:18 pm, edited 1 time in total.
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Loving Hearts upgraded

Postby claudiarabia » Tue Jul 25, 2006 10:46 am

Code: Select all
. . 9 1 . 2 5 . .
. 3 . . 4 . . 1 .
. . 2 . . . 6 . .
6 . . 3 . 4 . . .
. . . . 8 . . . .
. . . 7 . 5 . . 8
. . 5 . . . 2 . .
. 1 . . 9 . . 7 .
. . 6 8 . 3 9 .

Claudia
Last edited by claudiarabia on Wed Jul 26, 2006 4:56 am, edited 1 time in total.
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Posts: 288
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Re: Loving Hearts upgraded

Postby JPF » Tue Jul 25, 2006 12:31 pm

claudiarabia wrote:
Code: Select all
. . 9 1 . 2 5 . .
. 3 . . 4 . . 1 .
. . 2 . . . 6 . .
6 . . 3 . 4 . . .
. . . . 9 . . . .
. . . 7 . 5 . . 8
. . 5 . . . 2 . .
. 1 . . 9 . . 7 .
. . 6 8 . 3 9 .

Claudia


Claudia,
There are two "9" in column 5.

JPF
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Re: Loving Hearts upgraded

Postby claudiarabia » Wed Jul 26, 2006 8:58 am

JPF"][quote="claudiarabia wrote:[code]. . 9 1 . 2 5 . .
Claudia,
There are two "9" in column 5.JPF


r5c5 must be 8. I have already corrected. Thanks a lot.

Claudia
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Posts: 288
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Re: Another Solution for Claudiarabia's Puzzle

Postby claudiarabia » Wed Jul 26, 2006 9:06 am

Carcul wrote:Claudiarabia wrote:
Code: Select all
5 . . 1 . . . . 4
. . 8 . 2 . . . .
. 2 . . . 3 . . .
4 . . . . . 3 . .
. 5 . . 9 . . 7 .
. . 2 . . . . . 1
. . . 3 . . . 5 .
. . . . 8 . 2 . .
1 . . . . 4 . . 9 


This is a very good puzzle, and yes, it is harder than the previous one, but there is no need to dance.:D Carcul[/quote]
And here is the upgrade:

Code: Select all
9 . . 1 . . . . 4
. . 8 . 2 . . . .
. 3 . . . 7 . . .
4 . . . . . 6 . .
. 5 . . 6 . . 7 .
. . 2 . . . . . 1
. . . 3 . . . 5 .
. . . . 8 . 2 . .
1 . . . . 4 . . 3   Fraulein

Good look with solving!:)

Claudia
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Joined: 14 May 2006

Now with full 180° rotational symmetry and a bit harder!

Postby claudiarabia » Wed Jul 26, 2006 9:12 am

Carcul wrote:
Claudiarabia wrote:If I would add r9c7 it would become to easy.

It is still quite easy:.....This pattern is also very pleasant: is it possible to make your puzzle harder, Claudiarabia?
Thanks, Carcul


Yes it is!
Code: Select all
. . 4 . . . 5 9 .
. 9 . . . 6 . . 4
. 1 . . 7 . . . .
. 3 . . 8 9 . . .
. . 5 . 6 . 9 . .
. . . 3 4 . . 1 .
. . . . 2 . . 8 .
7 . . 5 . . . 3 .
. 8 6 . . . 7 . .


Happy solving, Carcul!

Claudia
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Re: Another Solution for Claudiarabia's Puzzle

Postby ravel » Wed Jul 26, 2006 12:00 pm

claudiarabia wrote:
Code: Select all
9 . . 1 . . . . 4
. . 8 . 2 . . . .
. 3 . . . 7 . . .
4 . . . . . 6 . .
. 5 . . 6 . . 7 .
. . 2 . . . . . 1
. . . 3 . . . 5 .
. . . . 8 . 2 . .
1 . . . . 4 . . 3   Fraulein


Thanks for this one: 4 steps/Explainer rating 9.2.
ravel
 
Posts: 998
Joined: 21 February 2006

Re: Another Solution for Claudiarabia's Puzzle

Postby claudiarabia » Thu Jul 27, 2006 9:30 am

ravel wrote:
claudiarabia wrote:
Code: Select all
9 . . 1 . . . . 4
. . 8 . 2 . . . .
. 3 . . . 7 . . .
4 . . . . . 6 . .
. 5 . . 6 . . 7 .
. . 2 . . . . . 1
. . . 3 . . . 5 .
. . . . 8 . 2 . .
1 . . . . 4 . . 3   Fraulein


Thanks for this one: 4 steps/Explainer rating 9.2.


My pleasure:) ! I made 3 versions of this pattern. Two of them Sudoku Explainer rated 9.0. I wonder if somebody ever reached the complete 10.

Claudia
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Astrology collection

Postby ravel » Thu Jul 27, 2006 12:44 pm

claudiarabia wrote:I wonder if somebody ever reached the complete 10.

AFAIK not yet. Nicolas Juillerat, the author of Explainer, wrote me, that the hardest he constructed himself was 9.4 and the best he knew of 9.8 (toughest known).


Here is an esoteric collection - with more or less recognizable signs.

Code: Select all
  . . . . . . . . .        . 9 1 . . . 6 4 .        . 3 5 1 7 2 9 4 .
  . 3 1 . . . 9 8 .        6 . . 1 . 2 . . 7        . . 9 4 . 3 7 . .
  8 . . 6 . 7 . . 5        . . . 6 . 7 . . .        . . . 9 . 8 . . .
  5 . . . 4 . . . 7        . . . 7 2 9 . . .        . . 3 . . . 1 . .
  6 . . . 3 . . . 2        . . 4 . . . 8 . .        . . 4 7 . 9 8 . .
  . . . 1 . 2 . . .        . 1 . . . . . 3 .        . . 2 . . . 6 . .
  . . . 8 . 1 . . .        . 5 . . . . . 1 .        . . . 6 . 7 . . .
  . . . 5 . 4 . . .        . . 2 . . . 3 . .        . . 8 2 . 1 4 . .
  . . 4 . . . 7 . .        . . . 3 1 4 . . .        . 6 7 5 9 4 2 8 .


  . . . 9 5 3 . . .        . . . . 2 4 . . .        . . . . . . . . .
  . 8 . . . 4 9 . .        . . . 9 . . 1 . .        . 3 4 5 8 1 2 . .
  7 . . . 1 . . 5 .        . . . 1 . . . 3 .        . 5 . 7 . 6 . 8 .
  . . . . 8 . . 3 .        . . . 3 . . . 5 .        . 4 . 8 . 3 . 9 .
  . 6 7 . . 5 8 . .        . . . . 6 . . 7 .        . 1 . 2 . 7 . 5 .
  8 . . 4 . . . . .        . 5 6 . 7 . . 4 .        . 7 . 9 . 4 . 6 .
  5 . . 6 . . . 7 .        8 . . 5 3 . . 2 .        . 9 . 4 . 2 7 . .
  . 9 3 . . . 6 . .        3 . . 6 . . . . 7        . . . . . 8 . . .
  . . 6 2 4 . . . .        . 2 1 . . . . . .        . . . . 9 . . . .


  . . . . . . . . .        . . 4 . 6 . . . .        . . . . . 6 1 7 3
  . . . 7 2 5 . . .        . 5 . 9 . 4 . . .        . . . . . . . 8 4
  . . 6 . . . 8 . .        . 6 . 7 . 1 . . .        . . . . . . 6 . 5
  . . 1 . . . 2 . .        . 9 . 4 . 5 . . .        . . . . 5 2 . . 9
  2 7 5 . . . 3 8 1        . 3 . 1 . 6 . . 7        2 . . . 1 7 . . .
  8 . . . . . . . 6        . 2 . 8 . 7 . 9 6        . 1 7 4 . . . . .
  . . . . . . . . .        . 7 . 5 . 2 . . 3        . 3 9 8 . . . . .
  . 4 9 . 1 . 7 2 .        . 1 . 3 . . 8 6 .        . 7 6 3 . . . . .
  7 1 . 2 . 8 . 9 4        . . . . . . . . .        8 . . . 7 . . . .


  . 6 . . 4 1 . 2 7        . . . . . . . . .        2 8 . . . . . 3 9
  . . 2 3 . . 5 . .        . 3 1 . . . 7 6 .        . . 6 . . . 1 . .
  . . . . . 8 . . .        4 6 . 9 . 5 2 . 3        . . . 7 . 3 . . .
  . . . . 3 9 . . .        3 . . . 6 4 . . 5        . . . 5 . 7 . . .
  . . . 6 . . 8 . .        . . . . . . . . .        . 6 9 3 1 2 5 8 .
  . . 9 4 . . . 5 .        . 4 9 . . . 6 2 .        . . . 6 . 8 . . .
  . . 3 1 . . . 4 .        2 . 6 3 . 1 . 7 8        . . . 2 . 9 . . .
  . . 5 8 2 . 9 . .        9 . . 4 8 2 . . 6        . . 1 . . . 3 . .
  . . . 9 7 3 . . .        . . . . . . . . .        3 4 . . . . . 2 6

All can be solved with basics (locked candidates, tuples), x(yz)-wing, UR (1,2,4) and turbot fish (note an easy to spot hidden quad in one puzzle).

Solving ones sign in a full moon night brings love, luck and money:)

For copying:
Code: Select all
..........31...98.8..6.7..55...4...76...3...2...1.2......8.1......5.4.....4...7..
.91...64.6..1.2..7...6.7......729.....4...8...1.....3..5.....1...2...3.....314...
.3517294...94.37.....9.8.....3...1....47.98....2...6.....6.7.....82.14...6759428.
...953....8...49..7...1..5.....8..3..67..58..8..4.....5..6...7..93...6....624....
....24......9..1.....1...3....3...5.....6..7..56.7..4.8..53..2.3..6....7.21......
..........345812...5.7.6.8..4.8.3.9..1.2.7.5..7.9.4.6..9.4.27.......8.......9....
............725.....6...8....1...2..275...3818.......6..........49.1.72.71.2.8.94
..4.6.....5.9.4....6.7.1....9.4.5....3.1.6..7.2.8.7.96.7.5.2..3.1.3..86..........
.....6173.......84......6.5....52..92...17....174......398......763.....8...7....
.6..41.27..23..5.......8.......39......6..8....94...5...31...4...582.9.....973...
..........31...76.46.9.52.33...64..5..........49...62.2.63.1.789..482..6.........
28.....39..6...1.....7.3......5.7....6931258....6.8......2.9.....1...3..34.....26
ravel
 
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Re: Astrology collection

Postby claudiarabia » Thu Jul 27, 2006 1:28 pm

ravel wrote:AFAIK not yet. Nicolas Juillerat, the author of Explainer, wrote me, that the hardest he constructed himself was 9.4 and the best he knew of 9.8 (toughest known).


Hi ravel,

Thank you once for the esoteric collection!

Thank you twice for listing Fraulein in the world's toughest toughies!

In your toughies-list there are at least two puzzles which were rated by SE with 9,9.

with best wishes
Claudia
claudiarabia
 
Posts: 288
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A diamond Sudoku

Postby claudiarabia » Sat Jul 29, 2006 8:38 pm

Code: Select all
9 . . . 1 . . . .
. . . 2 . 3 . 8 .
. . 8 . . . 7 . .
. 2 . . . . . 3 .
4 . . . 6 . . . 1
. 6 . . . . . 5 .
. . 3 . . . 6 . .
. 1 . 8 . 7 . . .
. . . . 4 . . . 5

Claudia
claudiarabia
 
Posts: 288
Joined: 14 May 2006

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