Re: [Haskell-cafe] Segment Tree based Set

It is not a Set, but a Map. Of course, I could use it to implement the function I need with something like: type SSet a = STree [()] a, but then I'd have to unnecessarily go beyond Haskell98. Hoping there might be an interval tree or segment tree specifically for this task. On 29/10/12 18:36, Roman Cheplyaka wrote:

If you searched hackage, you'd find http://hackage.haskell.org/package/SegmentTree

Roman

* Tony Morris [2012-10-29 15:38:07+1000]

...

Er, oops.

...can be implemented as: \a rs -> let s = Set.fromList (rs >>= \(a, b) -> [a..b]) in a `member` s

Something like that!

On Mon, Oct 29, 2012 at 2:48 PM, Tony Morris wrote:

...

Hi, I was wondering if anyone knows of a package implementing a fast lookup for an element in ranges.

For example, this operation: Ord a => a -> [(a, a)] -> Bool

...can be implemented: \a rs -> let s = Set.fromList rs in a `member` s

This is not particularly efficient. A segment tree seems like a more appropriate data structure to store the ranges. Does such a library exist?

-- Tony Morris http://tmorris.net/