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

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57
votes
7answers
4k 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 ...
7
votes
1answer
139 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 column contains the numbers 1-9 Each ...
11
votes
2answers
283 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 ...
13
votes
4answers
613 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 the format of your choice and ...
30
votes
14answers
4k 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 ...
10
votes
1answer
851 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 ...
6
votes
3answers
2k 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 ...
9
votes
0answers
965 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 ...
6
votes
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 ...
13
votes
0answers
617 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 ...
18
votes
11answers
3k 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. ...
26
votes
2answers
2k views

Implement a Non-Guessing Sudoku Solver

Implement the shortest Sudoku solver. Sudoku Puzzle: | 1 2 3 | 4 5 6 | 7 8 9 -+----------------------- A| 3 | 1 | B| 6 | | 5 C| 5 | | 9 8 3 -+----------------------- D|...