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Re: Trying to solve N-Queens

by talexb (Chancellor)
on Sep 09, 2002 at 02:50 UTC ( [id://196138]=note: print w/replies, xml ) Need Help??


in reply to Trying to solve N-Queens

Instead of looking at your code, I just visited one of the links that describe the problem, and have this approach to offer (to be coded as you choose).

The brute force method works (put a queen at (1,1) or top left, and place the next queens in the next column, and so forth) but it's a little inefficient. My approach would start off by placing a queen at (1,1), but the placement of the next queen would be in the next available location that is out of reach of all of the queens placed on the board so far. More queens would be placed in this manner until the number of uncovered places reached zero (solution!) or until we run out of queens.

--t. alex
but my friends call me T.

p.s. And I'm not sure why your second matrix shows

Q 0 0 rather than Q 0 0 1 0 1 0 0 1 1 1 0 0 1 0
Wouldn't the matrices be symmetric about the diagonal?

Replies are listed 'Best First'.
Re: Re: Trying to solve N-Queens
by Anonymous Monk on Sep 09, 2002 at 10:39 UTC
    If he is moving across by column, then there is no need to worry about marking and unmarking columns since he will never try placing 2 queens in the same column.

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