# Questions tagged [sudoku]

Sudoku (数独 sūdoku?, すうどく) English pronunciation: /suːˈdoʊkuː/ soo-doh-koo is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid (also called "boxes", "blocks", "regions", or "sub-squares") contain all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which typically has a unique solution.

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### Possible speed improvements for a Sudoku board validation algorithm?

I tested this algorithm on 9x9 boards and on average, if the board passed to the function is a (valid) solution, it takes 0.13-0.14 seconds for 1 million executions on my machine. I ran my code in ...
330 views

### Sudoku Game with automatically generated Sudokus

Project I've created a puzzle site with automatically generated sudokus. For more information on Sudokus, please see the wikipedia article. The code ...
606 views

### Sudoku solver program written in modern c++

This is a simple program that solves a given Sudoku puzzle recursively. The input is provided as a file that contains the cells, 0 if empty, delimited by a , ...
80 views

### Sudoku Solver using rules of Sudoku and backtracking

This code tries to solve the sudoku board using the rules of sudoku. When it does not make progress in solving, it assumes a cell value and tries again. Please review my code and help me understand ...
374 views

### Recursive Sudoku solver using Python

A Sudoku solver that works recursively. I'd appreciate your comments about coding style, structure and how to improve it. Thank you very much for your time. Code structure The Solver works by ...
91 views

### A valid Sudoku Generator without backtracking in JavaScript

I am new to programming. I tried to write a valid Sudoku solver with backtracking, the performance is disappointing. So, I tried to generate a valid Sudoku generator without backtracking. The white ...
138 views

### Generalised NxN Sudoku solver using heap

My implementation of a Sudoku solver. It isn't done using the most naive way but still it does an exhaustive search with some assistance from a heap. The only constraints I have used is the basic ...
134 views

### Python sudoku solver using backtrack algorithm

My first attempt at a sudoku solver using the backtrack algorithm. ...
68 views

### Sudoku solver using backtracting and depth-first-search

I've recently finished my first ever C program. I implemented a Sudoku solver that uses backtracking. Does my code look like a proper C-program? Are there any recommendations for improving my code? <...
338 views

### Made a sudoku solver with basic GUI in C++

I've made a sudoku solver which solves a sudoku, given user input, and can also extract digits from a picture of a sudoku to solve it. I've used OpenCV and GTK+ 2.0 to achieve the above. I am very ...
211 views

### Sudoku-Solver with GUI - follow-up

Background A few months ago, I asked this and this question on my implementation of a Sudoku-Solver. I now tried to further improve this little project. Changes Minor GUI-changes Input validation "...
6k views

### Simple Sudoku Solver in Python

This is my naive approach on implementing a Sudoku solver, which is okay for simple Sudokus like this: ...
227 views

### JavaScript Sudoku Recursive Solver

Thanks for all the great feedback in Part 1. I implemented a lot of it. Here is version 2. I am looking for feedback on: Recursive solve algorithm. It's too slow. I used Chrome DevTools Performance ...
40 views

### Sudoku seed generator

The code returns a string ready to seed at sites like sudoku-solutions.com. It works great but as I couldn't find other simple examples for my level I hope for some insights on this and ways to ...
3k views

### Sudoku game in JavaScript

PHP coder here. Learning JavaScript this week. I made a sudoku game for practice. Features: Import puzzles by pasting a text string. Imported squares are gray. Your squares are white. Program doesn't ...
80 views

### C backtracking Sudoku solver

I wrote this program in C to solve a given Sudoku puzzle (represented as 2D array) using backtracking algorithm. How can I make it more efficient, maybe faster and more C-onic? This is my first post ...
355 views

### Python sudoku solver with classes

I just coded an object-oriented Sudoku solver, but I don't have any possibility to check whether I have written good code, so I thought I would just post it here for review. I have looked for other ...
129 views

### Speeding up naive backtracking Sudoku Solver in Haskell

After watching a recent computerphile video on building a very simple sudoku solver I tried to implement the same in Haskell. From this CR question I learned that it is probably a better idea to use ...
141 views

### “Smart” sudoku brute-forcer

After running my C-brute-forcer for two days on a 25x25 sudoku, I decided to re-write in Java so that it would solve it in an acceptable time frame. The idea: Make smart fields that contain all ...
2k views

### Basic Sudoku Solver

For my programming class I had to make a sudoku solver. ...
191 views

### Python Sudoku Solver

I wrote this program for a Sudoku solver in Python. It utilizes tkinter GUI. I've uploaded the project to my GitHub. Please can you have a look and let me know of ...
167 views

### Sudoku-Solver - follow-up

I've now tried to use the suggestions you can find here to improve my Sudoku-Solver. Here's the updated code: ...
848 views

### Sudoku-Solver with GUI in Java

I've wrote a Sudoku-Solver in Java, which also contains a GUI, so you can just enter the Sudoku, press "OK" and it will solve the Sudoku using backtracking. Here's the code: ...
231 views

### Sudoku Board Generator

I am working on a Sudoku board generator that generators a valid complete Sudoku board. My algorithm generates a valid board, but the runtime is variable. Time varies from ~0.2 to 8 seconds. Ideally, ...
767 views

### Displaying a Sudoku Board

For my programming class, we have been tasked with creating a Sudoku solver; the first step of the project was to create a program which would display the game board based on input provided by the ...
152 views

### Validating sudoku columns and rows

I'm writing a sudoku col/row validator, what is does is: Reads user input on how many Sudoku instances to validate. Reads the sudoku matrix grid 9x9 (for me, in my specific case 9x9) into a 2d array. ...
73 views

### Sudoku validation

Problem explanation I've written a function to validate sudoku. Given a two-dimensional 9×9 array of numbers: Each row should have each of the numbers 1–9 exactly once. Each column should have each ...
253 views

### Creating an empty Sudoku grid

I am generating a 9x9 grid on which I will play sudoku later by setting click listeners to each square on the grid. I first have a .xml file that represents a single square in the grid. This consists ...
81 views

### Solving Sudoku using computer vision, feedback on class

I have made a project at Github that uses computer vision to solve Sudokus. Since this is my first project I would really like to get some feedback on my code. Since it is not allowed to link my ...
517 views

### How to make my backtraching sudoku solving algorithm in Python faster?

I wrote a backtracking Sudoku solving algorithm in Python. It solves a 2D array like this (zero means "empty field"): ...
927 views

### LeetCode #37: Sudoku as Exact Cover Problem solved using Dancing Links

Introduction I provide a regular 9x9 Sudoku solver, reducing the puzzle to an Exact Cover Problem. The algorithm used is Knuth'...
47 views

### Python script takes input of four elements and outputs a valid 4 × 4 Sudoku grid in O(n) time, but only when given non-repeating elements

Introduction I've found a clever and fun thing to do after solving a n2 × n2 sudoku puzzle. I can take a grid as such as this one and hard-code its indices as constraints to output other 4 × 4 latin ...
952 views

### Easy-Medium Sudoku solver written in Python - No recursion/ brute force

I'm very new to software developing, I wrote this Sudoku solver in Python, it's not the best approach ever I know and that is I guess because I started taking courses in Python and programming a month ...
118 views

### Sodoku solver with arrays of bitsets

I wrote a quick sodoku solver as an exercise and am curious how to make it faster. Parsing and printing is largely irrelevant only there for readability. How can I make the code cleaner and faster? <...
53 views

### Partial Sudoku Verifier

To practice my JavaScript for future employment, I've decided to take up the challenge of writing a javascript sudoku verifier. This code only verify's one of the ...
264 views

### Generate n^2 x n^2 Sudoku in poly-time

Introduction I have created an algorithm that generates n! Sudoku Grids in poly-time.I verified the correctness of my grids with a SAT solver up to 50x50. I'm awaiting a review for improvements. It ...
196 views

### Sudoku generator using seed Sudoku

I have created a Sudoku generator in Java. Here I am using a basic solved sudoku as seed and by transposing it and shuffling its row and columns I get a new solved sudoku. ...
4k views

### Simple recursive Sudoku solver

My Sudoku solver is fast enough and good with small data (4*4 and 9*9 Sudoku). But with a 16*16 board it takes too long and doesn't solve 25*25 Sudoku at all. How can I improve my program in order to ...
156 views

### Three stage Sudoku puzzle generator

This was my first time attempting a project like this, so I figured it would improve readability, and would also just be nice If I allowed each stage to be visualized. Also, this only generates them, ...
102 views

### Java Android Sudoku solver

I made a simple and non recursive Android Java Sudoku solver implementing Algorithm X with links inspired from dancing links. The code is on Github (start with the Solver class and the ...
3k views

### Skyscraper puzzle solver in Java [closed]

For an assignment, I have created a solver for the Skyscraper Puzzle: Each puzzle consists of an N×N grid with some clues along its sides. The object is to place a skyscraper in each square, with a ...
599 views

### Valid Sudoku in Swift

This is my solution to LeetCode – Valid Sudoku in Swift. ...
170 views

### Amateur Python Sudoku Solver

I'm self-taught in Python and would have a lot of room for improvement. I made this basic Sudoku Solver mainly in order to practice the use of Class creation. I would greatly appreciate any feedback ...
945 views

### Object Oriented Sudoku Solver in Python

I started learning Python and I am preparing Sudoku Solver as my first small project. I am also trying to learn unit testing. I thought it is a good idea to ask for suggestions before I start with GUI....
252 views

### NxN Sudoku Solver

I have written a Sudoku solver which can solve arbitrary NxN grids via backtracking. Since I'm relativly new to C any feedback is welcome. Code: ...
178 views

### Sudoku-lite challenge

You can find the problem here. The example: Column A, B, and C are each 3 and together equal 9: ...
2k views

### Sudoku solver using NumPy

I come from the R language and I gradually switch to Python (Numpy and Pandas). I coded this python code for fun to solve a Sudoku grid. Could you tell me if my code is pythonic enough? For example, ...
2k views

### Fast and flexible Sudoku Solver in C++

After seeing a lot of Sudoku solvers on Code Review I decided to implement my own. My implementation aims to be very fast and flexible, supporting some Sudoku variations (irregular boxes, extra ...