A Sudoku puzzle can have more than one solution, but in this case the kind of logical reasoning we described while discussing solving strategies may fall short. It turns out that for a Sudoku of rank n, at least n2-1 distinct symbols must be used for the puzzle to have a unique solution.
Should you ever guess in sudoku?
Sudoku does not require guessing. In fact, when solving Sudoku puzzles, you’re better off NOT guessing at all. Sudoku is a logic puzzle, using the power of simple deductive reasoning and process of elimination to fill in the gaps in the grid. Simply put – you don’t need luck to play Sudoku.
Can a Sudoku puzzle have a unique solution?
There is no law requiring that a published Sudoku have a unique solution. When I see a puzzle of any type, I expect from experience that the setter has promised a unique solution (or occasionally will say there are some number to be found).
What happens when the rank of a Sudoku increases?
As the rank of a Sudoku increases from n to n+1, the extra computational time needed to find a solution increases quite fast. This places the game of solving rank-n Sudoku puzzles in a class of problems that computer scientists have named NP-complete. An NP-complete problem satisfies the following two properties:
How to show a sodoku solution is unique?
Soduko is a CSP to 81 variables, one for each box. Using variable names from A1 to A9 for the top row (left to right), to I1-I9 for the bottom line. The blank boxes have the domain {1,2,3,4,5,6,7,8,9} and that they have already filled a domain consisting of a single value.
How is the number of bands and stacks unique to Sudoku?
The number of bands and stacks also equals N. The “3×3” Sudoku is additionally unique: N is also the number of row-column-region constraints from the One Rule (i.e. there are N =3 types of units ). A Sudoku whose regions are not (necessarily) square or rectangular is known as a Jigsaw Sudoku.
