Ulterior Puzzles

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

re: an old puzzle from rubylips

Postby Pat » Fri Jan 05, 2007 11:29 am

    while every "ulterior" puzzle requires box-to-line exclusion
    in the sense that it cannot be solved by "hidden singles" alone,

    the above example has an extra property --
      it requires box-to-line exclusion
      in the sense that it cannot be solved by "singles" + subsets.
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"an absolute marvel"

Postby Pat » Thu Jan 18, 2007 2:38 pm

tarek wrote:
gsf (2007.Jan.17) wrote:
      filtered ~2M generated symmetric puzzles from last March --

      [ 30 clues ]
Code: Select all
 7 4 . | 3 . 9 | . 5 1
 . 2 . | . . . | . 8 .
 5 . . | . 2 . | . . 3
-------+-------+------
 2 . . | 6 . 3 | . . 7
 . . . | . . . | . . .
 1 . . | 2 . 5 | . . 6
-------+-------+------
 6 . . | . 3 . | . . 2
 . 3 . | . . . | . 7 .
 9 5 . | 1 . 7 | . 3 8



an absolute marvel
    bonus:
    cannot be solved by "singles" + subsets
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Postby Pat » Thu Feb 15, 2007 2:57 pm

ravel (2007.Feb.12) wrote:
Code: Select all
 . . . | . . . | . . .
 . 6 8 | 1 . 5 | 4 3 .
 9 . . | . 4 . | . . 7
-------+-------+------
 3 . . | . 9 . | . . 2
 6 . . | . . . | . . 1
 . 5 . | . . . | . 7 .
-------+-------+------
 . . 9 | . . . | 5 . .
 . . . | 3 . 6 | . . .
 . . . | . 7 . | . . .




    bonus:
    cannot be solved by "singles" + subsets
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65 clues

Postby Pat » Wed Feb 28, 2007 1:39 pm

      [ 65 clues ]
Code: Select all
 9 7 . | . 4 8 | 3 1 6
 3 6 8 | 1 . 7 | . 4 .
 1 4 . | . 3 6 | 7 . 8
-------+-------+------
 2 1 9 | 3 7 5 | 8 6 4
 8 3 6 | 4 1 9 | 2 5 7
 7 5 4 | 8 6 2 | 1 3 9
-------+-------+------
 5 . 7 | 6 . 3 | 4 8 1
 4 8 3 | 7 . 1 | 6 . .
 6 . 1 | . 8 4 | . 7 3



seems a high number of clues -- has this been exceeded ?
( for a puzzle requiring box-to-line exclusion )
    bonus:
    cannot be solved by "singles" + subsets
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Nemo (2007.Jun.17)

Postby Pat » Sun Jun 17, 2007 8:18 am

Nemo (2007.Jun.17) wrote:

      [ 26 clues ]
Code: Select all
2..4....3.....2.6.5..8...4.4...3.5....52.86....8.5...2.3...1..7.1.5.....8....7..1


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




    bonus:
    cannot be solved by "singles" + subsets
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JPF (2007.Jun.27)

Postby Pat » Fri Jun 29, 2007 7:27 am

JPF (2007.Jun.27) wrote:

      [ 20 clues ]
Code: Select all
1.......2...3.4.....2...5...3..5..6....1.7....6..8..4...3...2.....6.8...5.......1


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




    bonus:
    cannot be solved by "singles" + subsets
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Postby Pat » Mon Jan 17, 2011 1:49 pm


    44 cells given

    8269.43.11...63.4.435..1..69.1.2....5423...1.7.3.15..22.4.381.531.....2.65.1427..
Code: Select all

 8 2 6 | 9 . 4 | 3 . 1
 1 . . | . 6 3 | . 4 .
 4 3 5 | . . 1 | . . 6
-------+-------+------
 9 . 1 | . 2 . | . . .
 5 4 2 | 3 . . | . 1 .
 7 . 3 | . 1 5 | . . 2
-------+-------+------
 2 . 4 | . 3 8 | 1 . 5
 3 1 . | . . . | . 2 .
 6 5 . | 1 4 2 | 7 . .

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Pat # 214 # (230246) #

Postby Pat » Mon Sep 30, 2013 12:44 pm


    7...8...2..1....3..4....7......538..8..42.......1....7..52..3...1.....8.2....7..6

    [ play ]

Code: Select all

 7 . . | . 8 . | . . 2
 . . 1 | . . . | . 3 .
 . 4 . | . . . | 7 . .
-------+-------+------
 . . . | . 5 3 | 8 . .
 8 . . | 4 2 . | . . .
 . . . | 1 . . | . . 7
-------+-------+------
 . . 5 | 2 . . | 3 . .
 . 1 . | . . . | . 8 .
 2 . . | . . 7 | . . 6


    bonus:
    cannot be solved by "singles" + subsets
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Re: Ulterior Puzzles

Postby Marty R. » Tue Oct 01, 2013 2:56 am

cannot be solved by "singles" + subsets


I think I solved it with those two plus Locked Candidates.
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chained pointing pairs

Postby Pat » Wed Oct 02, 2013 10:47 am

on page 5, RW (2006.May.29) wrote:
If you wish to simulate a human solver,
then chained pointing pairs should count as only one step:

Code: Select all
-----|-----|* | *
* X X|. . .|X | X
* X X|. . .|X | X
-----+-----+-----
| X X|. . .|X | *
| * *|-----|--|--
| X X|. . .|X | *
-----+-----+-----
| . .|. . .|. | .
| . .|. . .|. | .
| . .|. . .|. A .


A computer would first exclude A from r1c123,
then in step 2 exclude A from r456c1,
in step 3 exclude A from r5c79,
in step 4 exclude A from r1c9
solving r1c7=A.

If you are a human solver
that don't use pencilmarks
(or memorize the previous pointing pairs in any other way)
then the only way you can use the 2nd, 3rd and 4th pointing pair
is by immediately following up the first one.
That's how slicing and dicing works,
you don't stop as long as new lines are exposed.


got a bit carried away?
the 3rd move solves the A for c7
(4th move not needed)

anyway my puzzle provides a real example of a triple move

    7...81..2.21.74638.48..27151..7538..87.42.153...1.8..7.852..371.17..528.2..8175.6
    [ play ]
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Pat # 212 # (231005) #

Postby Pat » Thu Oct 31, 2013 12:12 pm


    .75...2..31.9.....6.9.....1.9.7....5.....43......1..8.2...4.8.......8.2...15....9

    [ play ]

Code: Select all

 . 7 5 | . . . | 2 . .
 3 1 . | 9 . . | . . .
 6 . 9 | . . . | . . 1
-------+-------+------
 . 9 . | 7 . . | . . 5
 . . . | . . 4 | 3 . .
 . . . | . 1 . | . 8 .
-------+-------+------
 2 . . | . 4 . | 8 . .
 . . . | . . 8 | . 2 .
 . . 1 | 5 . . | . . 9

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Re: Ulterior Puzzles

Postby 7b53 » Sun Nov 03, 2013 2:50 am

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

fun puzzle, what will be the key move...
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