Have a look at the thread below which catalogs the most clueful puzzles discovered at each Sudoku Explainer difficulty rating:
SE assigns a rating of 1.2 to puzzles that can be solved only with singles, so the max clue puzzles for anything beyond 1.2 would qualify. The ...
There's no no-computers, and it was easy enough to hack my Kyoto CNF generator to produce a SAT instance for the problem: a 9×9 bit array where each row, column and box has two 1s and no two adjacent variables may be both 1.
This answer does not user spoilers because what's being presented is not a solution that may be spoiled, but a strategy for reaching solutions. It is also (likely overly) long in an attempt to methodically demonstrate the strategy.
You may be able to use a logic grid to do this. Label the seats as so (ignore the header row):
Those in ...
I don't know how the other similar problems you're referring to looks like, but for the example:
B sits third to the left of A. G does not sit to the immediate left of B.
Now we can place:
And now we also can deduct that,
E does not sit between A and F.
Which means we get this arrangement:
In the rightmost column
If it were are the bottom, row 17 (always included in the 6) would force the 7 in the next column to the bottom too, but it wouldn't fit because of the 1 on row 18 (also always included in the 6) forces r18c19 to be empty.
Look at the 9th column (2,7,1):
Then in that row (4,9),
Then in that column (8,3),
That allows you to fill in quite a few cells in that column, which will then enable you to make more deductions in the relevant rows.
Graylocke has worked through an older version of the puzzle, which did not have a unique solution. If (s)he would had seen the updated puzzle, I’m sure that (s)he would have been able to solve it quickly using the same type of deductions which (s)he had been using.
However, since it’s been more than a year without any updates, I am posting my solution.
The difficulty level of sudoku is not determined by the amount of restrictions there are on the puzzle, but rather the level of skill and techniques required to solve the puzzle. The easiest of sudoku puzzles will require basic understanding of sudoku logic, whereas the hardest will require advanced techniques and understanding.
There is ...