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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27
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2answers
816 views

Pseudoku: A Game of Finding Order in Chaos

You are Pat Doe, a lowly Sudoku puzzle-maker eking out a living by producing hand-made Sudoku puzzles. After an exhausting eight hours, you've just completed your last Sudoku grid for the day. ...
3
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1answer
251 views

Non-Diagonal Pointing Problem

You can see the rules for pointing problem at this article. It has been clarified that there is no solution to this question. But, what if we remove the diagonal rule? is there any solution?
2
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2answers
689 views

SuDoKu Unique Rectangles and the “2 blocks” rule

On HuDoKu's page on Uniqueness, under Unique Rectangle, it says A common mistake when looking for URs is to violate the "2 blocks" rule (see the Sudopedia article for an example). Unfortunately, ...
7
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1answer
650 views

How do I necessitate the use of the X-Wing pattern during Sudoku creation?

I want to create a Sudoku puzzle, and I want it to be of moderate difficulty. There's a specific pattern I want to include, called the X-Wing pattern: This occurs when two numbers form locked ...
-1
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3answers
2k views

Why must a sudoku have a unique solution [closed]

Why must a sudoku have a unique solution. In my books I don't guarantee it. But I am sure there are not many which don't. I doubt if one in a thousand dont have. And even if they don't its only a ...
8
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1answer
600 views

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 ...
8
votes
1answer
336 views

How to deal with conjugate-pair pseudocycles when solving Sudoku

In single-solution regular Sudoku puzzles, sometimes you may encounter a combination of possible cell solutions such as: {2,7} in A1 and A7 (same row) {2,7} in A7 and B8 (same box) {2,7} in B8 and E8 ...