dailysudoku.com

[helen elford]

the Australian Puzzler Issue 117 puzzle 55 and possibly 56 has two solutions to the same puzzle. I checked on my sudoku computer and both appear right. Has anyone else come across this. A scientist was asked the question once and said the probability of two solutions to the same puzzle was astronomical. I would love to hear from others two have experienced what I have in this regard. helen.

[azoundria]

Yes. Some puzzles would have multiple solutions.

An empty puzzle has all possible placements of the numbers as solutions.

If you add a single number, there is now a smaller subset of solutions.

Each additional number reduces the possibilities.

You could eventually reduce that number to just one solution, or you could leave the puzzle in such a way that multiple solutions are correct. Puzzles with multiple solutions are harder because at some point you have to do a bit of guesswork to reach one of the solutions.

[keith]

If you post the puzzle we can comment. Multiple solutions are quite common, but published puzzles should be screened so they only have a single solution.

Keith