# Questions tagged [sudoku]

Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a $9\times9$ grid with digits so that each column, each row, and each of the nine $3\times3$ subgrids that compose the grid (also called "boxes", "blocks", "regions" or "subsquares") contain all the digits from $1$ to $9$. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a unique solution.

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### Does this linear function exist?

I'm trying to solve Sudoku using linear programming. In Sudoku, it is known that each row and column of the grid must contain number from 1 to 9 without duplicates. I need a constraint function that ...
• 103
1 vote
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### How many different $2 \times 2$ Sudokus are there?

PROBLEM How many different $2 \times 2$ Sudokus are there? APPROACH This seems pretty easy to brute force. There are $576$ Latin squares of size $4$ (which are the sudokus without restriction on boxes)...
• 247
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### Sudoku Puzzle with only 1 and 0 and other restrictions

For the following sudoku-style puzzle, you are given the following 9-by-9 grid, and you need to fill it in with zeros and ones satisfying the following conditions: (i) Each row, each column, and each ...
• 918
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### Minimum Number of Clues for Unsolvable Sudoku

I am going to make a distinction between "unsolvable" and "invalid" Sudoku. A Sudoku is unsolvable if there is no way to fill in all the spaces without violating one of the rules ...
• 173
1 vote