I'm looking for a data structure that allows O(1) querying if a value is contained in the data structure, and reasonably fast construction of the data structure given that the initial size is unknown (although this criteria is not that strict). I was looking at the Set in base, but I can't find a way to test if a Set contains contains a particular value. I also don't know about the efficiency of appending to a Set. Any suggestions or information about Set would be appreciated.
Jared Crean
