I wrote -

>  As an 
> example The Fast
> Fourier Transform is an example of divide-and-conquer.  A brute-force
> spectral transformation takes O(n^2) time, which is prohibitive for
> large data set.  Using the FFT technique reduces the time to O(ln n),
> which can make for huge decreases in processing time.  
> 

I meant O(n ln n), of course.

Cheers,

Tom P

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