The New Sudoku Players' Forum

[maria45]

Hello you programmers,

just played around a bit with sudoku explainer, and I came upon some puzzles which differ only in one number in the same cell:

5..7...1..6..4...7..3..24....48..2...1..3..8.2....9..4..86..3...3..2..5.9....5..6
5..7...1..6..4...7..3..25....48..2...1..3..8.2....9..4..86..3...3..2..5.9....5..6
5..7...1..6..4...7..3..26....48..2...1..3..8.2....9..4..86..3...3..2..5.9....5..6
5..7...1..6..4...7..3..28....48..2...1..3..8.2....9..4..86..3...3..2..5.9....5..6
5..7...1..6..4...7..3..29....48..2...1..3..8.2....9..4..86..3...3..2..5.9....5..6

Despite the complicatedly looking pattern with many diagonal givens, all five puzzles solve with singles.

I wonder wether there are other puzzles like this, differing in only one given in the same cell and how many different puzzle are possible with this variation, and if there could exist a puzzle with all nine possible values in a cell, each resulting in a valid (i.e. with unique solution) sudoku.

[JPF]

I wonder wether there are other puzzles like this, differing in only one given in the same cell and how many different puzzle are possible with this variation, and if there could exist a puzzle with all nine possible values in a cell, each resulting in a valid (i.e. with unique solution) sudoku.

I posted this one, 2 months ago :

Code: Select all

[3,4,5,8,9 are valid digits in A = r4c9]

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



So far, my personal record is 5 .
[Edit : wording]

JPF

[ravel]

Puzzles with 2 possible givens in the same cell were called twins by gfroyle. I have tried some (harder ones) and noticed that the solution paths were very similar.
But this is not the case for JPF's puzzles. The puzzle with 3 needs a chain, with 9 it is singles only.

[JPF]

one other example :

Code: Select all

r3c9 = [1,2,5,6,9]

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



JPF