[Haskell-cafe] 14-queens Problem

ajb at spamcop.net ajb at spamcop.net
Sun Oct 2 20:29:52 EDT 2005

G'day all.

Quoting Yousry Abdallah <yousry_abdallah at hotmail.com>:

> is it fast to calculate all solutions for the 14-queens problem in 7
> minutes?


    % time ./queens 14
    365596 solution(s).

    real    0m4.045s
    user    0m3.928s
    sys     0m0.008s

The program is a minimal cover solver written in C++ (about 500 lines,
including the n-queens-specific part) running on a 2GHz Pentium 4.

Having said that, whether or not it's "fast" depends very strongly on
what you're doing with the solutions.  In the above program, I'm just
counting them.  In Haskell, please be aware that printing a result can
often be MUCH more expensive than computing it.

Andrew Bromage

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