On 1/27/12 3:07 PM, sclytrack wrote:
On 01/27/2012 08:36 PM, Andrei Alexandrescu wrote:
Here's a multikey sorting problem that's bothering me; I think it's well
researched but I can't find the right keywords.
Say we have a collection of people with height and hair length
information. We want to get people who are "tall and long-haired". More
precisely, we want to order people by rank(p.height) +
rank(p.hairlength), where rank(p.k) is the function that returns the
rank of person p if ordered by key k.
The brute force approach would essentially compute the two ranks and
then sort by their sum. That's three sorts and at least one temporary
array. But I think things can be done considerably better. Any ideas?
Thanks,
Andrei
http://en.wikipedia.org/wiki/K-d_tree
Thanks. I think k-d trees are good for general operations (insertion,
deletion, and nearest neighbor query) whereas here we're interested in
sorting.
Andrei
