# Questions tagged [sudoku]

This challenge is directly related to solving, creating, or otherwise working with sudoku puzzles.

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9answers
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### The fastest Sudoku solver

Winner found It seems as if we have a winner! Unless anyone plans on contesting the world's current fastest Sudoku solver, user 53x15 wins with the staggeringly fast solver Tdoku. For anyone still ...
4answers
3k views

### Implement a Non-Guessing Sudoku Solver

Implement the shortest Sudoku solver. Sudoku Puzzle: ...
5answers
967 views

### Build a minimum-clue Sudoku unsolver

My attempt at stating this question, but with a more objective solving criterion. Your task is to build a program or function that takes a solved Sudoku grid S in ...
4answers
272 views

### Counting valid Binary Sudoku boards

Sequel of Counting valid Binary Sudoku rows. Background Binary Sudoku, also known as Takuzu, Binario, and Tic-Tac-Logic, is a puzzle where the objective is to fill a rectangular grid with two ...
13answers
1k views

### Counting valid Binary Sudoku rows

Background Binary Sudoku, also known as Takuzu, Binario, and Tic-Tac-Logic, is a puzzle where the objective is to fill a rectangular grid with two symbols (0s and 1s for this challenge) under the ...
2answers
570 views

### Create a diagonal sudoku board

A Diagonal Sudoku board is a special case of Latin squares. It has the following properties: The board is a 9-by-9 matrix Each row contains the numbers 1-9 Each ...
3answers
277 views

### Is this board Latin-style?

Inspired by Flow Fit: Sudoku, a brand-new mobile puzzle game (as of Nov 2019). Background A Latin square is a square grid of side length $n$ filled with $n$ different symbols, where each row ...
13answers
5k views

### Implement a Brute Force Sudoku Solver

Implement the shortest Sudoku solver using guessing. Since I have received a few request I have added this as an alternative question for those wishing to implement a brute force sudoku solver. ...
3answers
4k views

### Build a Killer Sudoku Solver

You thought regular sudoku was hard, now try Killer Sudoku! In the game of Killer Sudoku, you aren't given any numbers at all. Instead, you're given regions that are said to add up to a certain ...
1answer
241 views

### Morse sudo-ku-de

Hehe, see what I did with the title? Anyways... Your job is to create a sudoku solver that accepts input in Morse code and creates output in Morse code. Here's the Morse code numbers for reference: <...
1answer
530 views

### Maximize Sudoku King's tour

Background Sudoku is a number puzzle where, given an $n \times n$ grid divided into boxes of size $n$, each number of $1$ to $n$ should appear exactly once in each row, column and box....
25answers
5k views

### Output a Sudoku board

Today's challenge is simple: Without taking any input, output any valid sudoku board. In case you are unfamiliar with sudoku, Wikipedia describes what a valid board should look like: The objective ...
0answers
141 views

### Validate Sudoku (N by N) [duplicate]

Challenge : Create a random (pseudo random) Sudoku board with dimension n x n Input : Given : ...
4answers
648 views

### Find the rows which make each column have one True (was: Knuth's Algorithm X)

Task Given a Boolean matrix, find one (or optionally more) subset(s) of rows which have exactly one True in each column. You may use any algorithm, but must support very large matrices, like the last ...
1answer
1k views

### Unique Sudoku Finder

Challenge: Given a Sudoku board on standard input, find the minimum number of numbers added to make the board unique. Specifics/Rules: The input is formatted as follows (all whitespace is ...
20answers
5k views

### Create a sudoku solution CHECKER

Create a Sudoku solution CHECKER There are oodles of Sudoku SOLVERS here, but I want you to create a solution CHECKER as small as humanly possible (code-golf). A valid entry will be able to either ...
7answers
5k views

### Regex Golf: Verify a Sudoku Solution

Write a regex which matches any valid sudoku solution and doesn't match any invalid sudoku solution. The input is an unrolled version of the sudoku, i.e. there are no line delimiters. E.g. the ...
5answers
391 views

### Retrieve all possible marks that can be placed in a Sudoku puzzle [closed]

Given a Sudoku puzzle, find all possible marks that can be filled into each empty cell. Test case Input: ...
2answers
517 views

### Y-Wing Strategy for Sudoku

I recently got a new Sudoku app that produces really hard Sudoku's, which can't be solved using the standard strategies. So I had to learn a few new ones. One of these strategies is the Y-Wing ...
14answers
6k views

### Sudoku Compression

Your job is to write a program (or two separate programs) in any language that: Can take a completed Sudoku board as input (in any logical format) and compress it into a string of characters Can take ...
0answers
1k views

### Minimal Sudoku Generator [closed]

Ask questions if you need to, I'll elaborate on anything that needs clarified. My challenge is to unsolve a sudoku to a minimal state. Basically take a supplied, solved, sudoku board and unsolve it ...
1answer
1k views

### How many Sudoku puzzles exist?

This is not a Sudoku solver, nor a Sudoku checker. Your challenge is to write a function or script that, given as input the "block" size of a 2D Sudoku puzzle (which is 3 for the classic 9x9 board, 4 ...
1answer
2k views

### Sudoku board generator

A program that randomly generates a Sudoku game board with varying degrees of difficulty (however you decide to measure difficulty). Sudoku requires that there is only one solution, so your program ...