The New Sudoku Players' Forum

[m_b_metcalf]

Following on from the X-Alphabet, I thought to generate a short series of X-Digits. Hope it's of some interest.

Mike

Code: Select all

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

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


and one with 18 clues:

Code: Select all

 . . . 1 2 3 . . .
 . . 3 . . . 4 . .
 . . . . . . . 1 .
 . 5 . . . . . 3 .
 . 6 . . . . . 7 .
 . 8 . . . . . 6 .
 . . . . . . . 9 .
 . . 8 . . . 1 . .
 . . . 9 5 8 . . .   extremely difficult, 18 clues


[Hajime]

The first I could solve with Generalized Intersections and a XY-Wing.
The others are only solvable with guessing.
I found 1 diamond (maybe not minimal) and a nice pearl (minimal), for the collection...

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...823.....1...4...5.....6..7.....4..8.....9..2.....8..9.....1...7...6.....264...   ED=2.6/2.6/2.6
...173.....2...4...5.....6..7.....4..8.....9..2.....8..3.....1...7...8.....246...   ED=9.1/9.1/2.6

[m_b_metcalf]

I found 1 diamond (maybe not minimal)

Code: Select all

...823.....1...4...5.....6..7.....4..8.....9..2.....8..9.....1...7...6.....264...   ED=2.6/2.6/2.6


Definitely not minimal. Here's a minimal version:

Code: Select all

...8.3.....1...4...5.....6..7........8.....9........8..9.....1...7...6.....264...  17 clues, ED=9.0/4.3/2.9

Mike

[Hajime]

Because the first puzzle was not minimal, I did not pursue strict for minimals.

Definitely not minimal. Here's a minimal version:

Code: Select all

...8.3.....1...4...5.....6..7........8.....9........8..9.....1...7...6.....264...  17 clues, ED=9.0/4.3/2.9

....but not a diamond.... ?

I see now: from the diamond you erased some clues to get a minimal

[Pat]

The first I could solve with
Generalized Intersections and a XY-Wing.

if it needs XY-Wing
then exceeds 4.0

[1to9only]

10.x

Code: Select all

...123.....3...5...6.....1..7.....3..4.....7..8.....5..3.....2...4...1.....965... ED=10.3/10.3/2.6
...123.....3...5...6.....1..7.....3..4.....8..8.....5..3.....2...4...1.....975... ED=10.1/10.1/2.6
...126.....3...5...6.....1..7.....4..4.....7..8.....5..3.....2...4...1.....985... ED=10.0/10.0/2.6


[m_b_metcalf]

10.x

Code: Select all

...123.....3...5...6.....1..7.....3..4.....7..8.....5..3.....2...4...1.....965... ED=10.3/10.3/2.6
...123.....3...5...6.....1..7.....3..4.....8..8.....5..3.....2...4...1.....975... ED=10.1/10.1/2.6
...126.....3...5...6.....1..7.....4..4.....7..8.....5..3.....2...4...1.....985... ED=10.0/10.0/2.6


Wow!

[1to9only]

10.x

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...126.....3...5...6.....1..7.....4..4.....7..8.....5..3.....2...4...1.....985... ED=10.0/10.0/2.6


The 10.0 is interesting, as removing the 4 at r5c2 makes the sudoku-X minimal and ED=10.3!

Code: Select all

 . . . 1 2 6 . . .
 . . 3 . . . 5 . .
 . 6 . . . . . 1 .
 . 7 . . . . . 4 .
 . . . . . . . 7 .
 . 8 . . . . . 5 .
 . 3 . . . . . 2 .
 . . 4 . . . 1 . .
 . . . 9 8 5 . . . ER=10.3/10.3/2.6