N-Queens Puzzle API

This project creates an API using FastAPI to calculate solutions for the N-Queens problem and store them in a PostgreSQL database. You can generate solutions for different values of n (size of the chessboard and number of queens) and retrieve the stored solutions via API endpoints.

Features

• Calculate solutions to the N-Queens problem for any board size n between 1 and 11.
• Store the solutions in a PostgreSQL database.
• Retrieve all stored solutions or a specific solution by its order.

Requirements

• Docker
• Docker Compose

How to Run the Project

1. Clone the repository:

   git clone https://github.com/gmorales96/eight_queens_puzzle.git
   

2. Create a .env file with the following variables:

   DB_USER=admin
   DB_PASSWORD=mypassword
   DB_NAME=eight_queens
   

3. Build and run the project using Docker Compose:

   docker-compose up --build -d
   

4. To stop the project:

   docker-compose down
   

API Endpoints

Generate N-Queens Solutions

To generate solutions for an n x n chessboard, make the following POST request:

curl --location 'http://127.0.0.1:3003/api/solutions/generate' \
--header 'Content-Type: application/json' \
--data '{
  "n": 8
}'

The n parameter specifies the size of the chessboard and the number of queens. Example: Setting "n": 8 generates solutions for the 8-Queens problem.

Retrieve All Stored Solutions

To fetch all solutions stored in the database, use this GET request:

curl --location 'http://127.0.0.1:3003/api/solutions'

Retrieve a Specific Solution

To retrieve a specific solution by its order in the database, use this GET request:

curl --location 'http://127.0.0.1:3003/api/solutions/2'

Replace 2 with the order of the solution you want to retrieve. For example, use /solutions/1 to get the first stored solution.

Testing

Unit tests are provided for the N-Queens solution logic using pytest. To run the tests:

1. Create a virtual environment:

   python -m venv .
   

2. Activate the virtual environment:

   • On Linux

     source bin/activate
     

   • On Windows

     .\Scripts\activate
     

3. Install the necessary dependencies, including pytest:

   python -m pip install -r requirements.txt
   

4. Run the tests:

   pytest .\tests\test_queens_problem.py