Questions tagged [sudoku]
A Sudoku is a puzzle consisting of a grid to be filled with symbols, such that each constraining unit contains each symbol exactly once. The typical example is a 9x9 square to be filled with the numbers 1 to 9, where the constraining units are rows, columns, and 3x3 blocks.
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What is a good notation for trial-and-error when solving Sudoku on paper?
When solving Sudoku on paper, I sometimes get to the point where I need to resort to guessing or bifurcation. At that point, I might guess one number, and continue solving, changing that guess if I ...
user121
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Minimum number of clues for a sudoku puzzle
In a sudoku puzzle, what is the absolute minimum number of clues that must be given to specify a layout with a unique solution? Is one in each row, column, and box (9 total) necessary or sufficient?
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How to avoid getting "stuck" while generating sudoku puzzles?
I understand the basic method of generating sudoku puzzles, which is:
Put a random number in the current square.
If the puzzle is still valid, go to the next square. Otherwise, stay on the same ...
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What are the criteria for determining the difficulty of Sudoku puzzle?
What are the criteria for determining the difficulty of Sudoku puzzles?
Is it a subjective estimation based on the author's experience, or are there any precise guidelines?
For example, there are ...
user66
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Are there published Sudoku puzzles that require guessing?
I believe in a number of books I have read and solved myself, the introduction stated that guessing should never be necessary for any of the puzzles in the book. Instead, a handful of techniques ...
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What is the maximum number of solutions a Sudoku puzzle can have?
I've seen Sudoku puzzles that can be solved two different ways. Referring to a traditional 9x9 grid:
Is it possible for a Sudoku puzzle to have more than two solutions? If so, what is the maximum ...
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