https://github.com/mericluc/ecv-queens

ECV Application : N Queens
https://github.com/mericluc/ecv-queens

cpp cpp17 dlx-algorithm n-queens qt qt5

Last synced: 19 days ago
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ECV Application : N Queens

• Host: GitHub
• URL: https://github.com/mericluc/ecv-queens
• Owner: MericLuc
• Created: 2022-11-10T17:15:29.000Z (about 2 years ago)
• Default Branch: dev
• Last Pushed: 2022-11-12T19:58:22.000Z (about 2 years ago)
• Last Synced: 2023-03-28T00:45:32.986Z (almost 2 years ago)
• Topics: cpp, cpp17, dlx-algorithm, n-queens, qt, qt5
• Language: C++
• Homepage:
• Size: 1.28 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# ECV - Sudoku

**:star2: Exact cover problem - N Queens application :star2:**

Graphic toy written in C++/Qt to solve the [**N Queens problem**](https://en.wikipedia.org/wiki/Eight_queens_puzzle).

Under the hood, it uses the [**ECV library**](https://github.com/MericLuc/ecv) that implements [Donald Knuth's Algorithm X](https://arxiv.org/pdf/cs/0011047v1.pdf). 

![example](imgs/example.gif)

## How to build/install

_Dependencies_ : 

  - Qt5 (Qt5::Widgets Qt5::Svg packages)

  - ecv (as a submodule)

Start by getting the sources :

```

[~/git] git clone https://github.com/MericLuc/ecv-queens.git

[~/git] git submodule update --init --recursive

```

Then, the easiest way to build is to use it as a QtCreator project.

Otherwise, you can build from command-line using cmake and defining a bunch of Qt related variables.

It should be something like that (not garanteed) : 

```

[~/builds] cmake -S ${PATH_TO_PROJECT} -B ${PATH_TO_BUILD} -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=${PATH_TO_QT_INSTALL}

[~/builds] make

```

## Example usage

[**Play**](https://mericluc.github.io/ecv/queens/app.html) in your browser using a [webassembly](https://webassembly.org/) compiled version.

_Rules_ : 

  - Hover a cell to select it.

  - Left-click to add/remove a queen to a cell.

  - For the rest, I think the UI buttons are self-explanatory 😁

## Acknowledgements

[This article](https://www.nohuddleoffense.de/2019/01/20/dancing-links-algorithm-x-and-the-n-queens-puzzle/) was pretty useful, especially to realize the concept of "primary/secondary" constraints in exact-cover problems.