HashSet package:hashmap

Persistent Set based on hashing, which is defined as
data Set e = IntMap (Some e)
is an IntMap indexed by hash values of elements, containing a value of Some e. That contains either one e or a Set e with elements of the same hash values. The interface of a Set is a suitable subset of IntSet and can be used as a drop-in replacement of Set. The complexity of operations is determined by the complexities of IntMap and Set operations. See the sources of Set to see which operations from containers package are used.
Deprecated: HashSet is deprecated. Please use Set instead.