Sudoku
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Are you a fan of Sudoku? In it, a 9 by 9 grid needs
to be completed so that each row, each column and each of the 9 main 3 by 3
sub-grids contains just one of each of the numbers 1 to 9. At outset, the grid
is partly filled in. Your task is to complete the rest of the grid.
Have you graduated to the Killer Sudoku? It has the
same 9 by 9 grid, but (usually) none of the grid is filled in at outset.
Instead, the grid contains a further mesh of smaller groups of cells. Within
each such group, no number can be repeated and you are also told how much they
add up to. So, if the group contains just 2 cells and totals 3 you know that
one of its two cells must contain the number 1 and other must contain the
number 2, but you don't immediately know which one is which.
Or do you prefer the larger scale Samurai Sudoku
puzzles? These involve multiple overlapping 9 by 9 grids. There are other
variants too.
Solving Sudoku puzzles
There are several commercially available Sudoku solvers.
Some are provided by stand-alone electronic devices or bespoke programs that
you can buy, but most of these concentrate just on solving the ‘basic’ type of
Sudoku puzzle described above. Sudoku enthusiasts have fewer options (other
than, of course, their own brains!) if they want to access solvers for the more
complicated variants, such as Killer Sudoku.
The Nematrian website provides interactive tools for solving
several different types of Sudoku puzzle, including the mathematically more
challenging Killer Sudoku puzzles. These all make use of the same generic
Nematrian Sudoku Solver web service that computer programs and spreadsheets can
access directly via the web.
Happy solving!
Links to pages containing
solvers for:
-
Killer Sudoku
-
(Standard) Sudoku