On 17 May 2010 16:41, David Harkness <davi...@highgearmedia.com> wrote:
> Shahrzad,
>
> While your algorithm is correct it is very inefficient. The full array is
> scanned for every element in the array. If the array contains 1,000
> elements, 1,000,000 comparisons will be performed and mktree_array() will be
> called 1,000 times. This is known as order n squared: O(n^2) and is about as
> slow as it gets.
>
> Oh, I see that you "have to use [a] recursive function." Is this is a
> homework assignment? If not and you want to make it faster, you can speed up
> the code by creating a new array first that maps from $a['nid'] => $a (the
> array element) to create a hash table. Then loop over the array again and
> use the hash table to find the parent of each element ($a) and add it to $a.
> This will be much faster without being any more complex (exchange recursion
> for two simple loops).
>
> Peace,
> David
>

OOI, can you take a look at my first response. Is this the sort of
thing you were talking about?


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