nqueens's Introduction

nqueens.py

Calculates count of solutions for N-Queen problem.

General information

N-Queen problem - you need N chess queens on a chess board with dimensions NxN in a way that they do not threat each other (according to chess rules).

Program can find all possible solutions for N-dimensional board. Also, program able to print available solutions to console or to the file.

Usage

Command line keys

Options:
  -h, --help            show this help message and exit
  -d DIMENSIONS, --dimensions=DIMENSIONS
                        Dimensions for chess board
  -p, --printsolutions  Prints solutions

By default program will calculate solutions count for 8 dimensional board and will not print solutions.

Usage

With solutions on the screen

Calculate solution for 4 dimension board and print to console:

$ nqueens.py -p -d 4

You will got something like this:

2017-04-18 20:46:20,629 - DEBUG - solver initialized for chessboard size: 4
2017-04-18 20:46:20,630 - INFO - solution:
_ _ Q _
Q _ _ _
_ _ _ Q
_ Q _ _
2017-04-18 20:46:20,633 - INFO - solution:
_ Q _ _
_ _ _ Q
Q _ _ _
_ _ Q _
2017-04-18 20:46:20,635 - INFO - solutions search complete, found solutions coun
t: 2
2017-04-18 20:46:20,636 - INFO - total solutions count - 2
2017-04-18 20:46:20,637 - INFO - done at 0.01s
Done

Where:

_ _ Q _
Q _ _ _
_ _ _ Q
_ Q _ _

one of possible solutions.

Calculating solutions count

When you need just count solutions count, you can execute nqueens using:

$ nqueens.py -d 8

You will get someting like this

2017-04-18 20:47:49,566 - DEBUG - solver initialized for chessboard size: 8
2017-04-18 20:47:49,605 - INFO - solutions search complete, found solutions count: 92
2017-04-18 20:47:49,606 - INFO - total solutions count - 92
2017-04-18 20:47:49,607 - INFO - done at 0.04s

So, total solutions count for 8-dimensional board is 92.

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