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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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2answers
3k views

Examples of sudokus with two solutions [duplicate]

I need some examples of sudokus having more than one solution. Do these puzzles have any common things?
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1answer
294 views

How can I solve this Sudoku without guessing?

I am fairly new to Sudoku and have hit a brick wall with this one. My colleague said it can only be solved with a guess and seeing how far you go. However, I agree with many on this site and you ...
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2answers
208 views

Sudoku puzzle - where to go next?

Above is a link to a half-solved sudoku puzzle. I tried to fully solve it but just cant figure out what to do now. Source: Sudoku-Branium studios It is an app on google playstore.
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2answers
229 views

Sudoko-net pseudo-solvable with minimum blocks

A sudoku net is defined here. A sudoku net is defined as 'pseudo-solvable' if we can deduce at least two valid 'not unique' solutions . friendly sudoko is defined here What is the sudoku ...
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1answer
5k views

Check sudoku solvability

With a blank grid, I put and number (1-9) any cell, the Sudoku has n solutions. I continue filling any blank cells with numbers that satisfy the constraints, so the Sudoku still has many solutions, ...
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1answer
281 views

Generate a sudoku puzzle with minimum number of entries that has exactly $k$ solutions

Is there an algorithm to generate a sudoku puzzle having the minimum number of entries that has exactly $k>1$ solutions? What is this minimum number of entries, as a function of $k$? Given that ...
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3answers
170 views

Sudoku Move Marked Wrong, Seems Legal: Software Bug? [duplicate]

The included screenshot shows an attempted Sudoku move. The computer is marking it incorrect. There is no other 7 in the row, column, or 3x3 cell. What gives?
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1answer
532 views

Help solve sudoku

I did solve this sudoku in 24 minutes, but I had to guess from this part out. I'm using a website to display this sudoku a lot neater than the original site. I can solve plenty of sudokus, but the ...
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2answers
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Arrange to get sum of 450 when it is added row wise and column wise

I just came across a maths puzzle,where i should get the sum of 9 numbers(multiples of 10) to be 450 both horizontally and vertically in a 9x9 matrix. Picture attached for reference:
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1answer
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What should be my next valid move?

That's the stage I'm now. I am looking at G block (one in left down corner) 4,5 value. I couldn't decide if it should be 4 or 5. How do I decide? And, am I looking at the right place? Any alternate ...
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2answers
178 views

Stuck on this Sudoku puzzle. Please Explain the logic

I have completed this puzzle with the help of hints from the app. But I am not able to figure out the logic. I normally proceed by placing sure (unambiguous) digits first. Then repeat. But here I am ...
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1answer
113 views

Minimum number of clues for Sudoku to have an unique solution? [duplicate]

I already know that 17 clues are a minimum for a Sudoku to have a solution, but I don't consider a Sudoku to be a real Sudoku while having more than one solution.
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92 views

The hardest one I believe [duplicate]

If you are really smart solve this Sudoku within a day BEST OF LUCK
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3answers
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Can a 9x9 sudoku with sum 45 and square sum 285 of (rows, columns, 3x3) not be valid? [closed]

I have created a program that checks if a Sudoku solution is correct. It tries to do so by checking the following: Rows, columns, 3x3 grids if the sum of the numbers is 45 $(1+2+3...+9=45)$ Rows, ...
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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 ...
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2answers
266 views

SUDOKU What next? [closed]

I have solved up to this point. How do I proceed without guessing?
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2answers
235 views

How does one make a program to provide all the 'possible' numbers in an empty cell

To be able to solve a sudoku one usually has to first work out all the 'possible' numbers in an empty cell. How can one make a program to do this? In this case 'possible numbers' are ones which have ...
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2answers
252 views

Amazing sudoku who can find hot numbers

Sudoku X Place the numbers 1-6 once in every row, column, diagonal, and 3x2 block. The diagonals form an X and are highlighted. Puzzle Text of puzzle ----------------- | . . . | 5 . . | | . . . | ...
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2answers
212 views

What is wrong with this Sudoku Game?

Before you, you have a game. There's something wrong with this game. Can you figure out what it is? ...
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2answers
145 views

Numberless Sudoku with Just a Letter and Symbol Combination

A Standard 9x9 Sudoku uses the digits 1 to 9. You are only allowed to use a single letter(say T) and a symbol of your choice to represent the digits 1 to 9. Rules should be well defined and the ...
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2answers
1k views

Sudoku puzzle #1

Please solve the following sudoku puzzle (from Wikipedia):