Re: [MLUG] N-Queens Problem Solver

[Mike Miller <EMAIL:PROTECTED>]

On Thu, 17 Apr 2008, Michael Stegeman wrote:

> Hey, not sure if any of you will find this at all useful or interesting, 
> but I wrote a program that solves the N-queens problem using a simulated 
> annealing algorithm very, very quickly.  I solved a 100x100 problem in 
> just over 5 minutes, running at 1.83 GHz.  If you download, open up the 
> source file and change "#define N 20" to whatever number you'd like. 
> Let me know what you think!

I think it's really cool.  I was not familiar with this problem.  It does 
seem that some people are interested in the number of possible solutions 
for an NxN board.  For example, for the 20x20 board, there are, 
supposedly, 39,029,188,884 solutions.  It is hard to count them all 
quickly.  This programmer claims to produce that number just given for the 
20x20 board in about 20.5 minutes with an 800 MHz processor:

http://jsomers.com/nqueen_demo/nqueens.html

I like your output:

Solution for 30x30 Puzzle:
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Best,

Mike

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