18.4 Other Collection Types in the Standard Library
Beyond Vec
, String
, and HashMap
, the standard library offers more collections:
BTreeMap<K, V>
: A balanced tree map with O(log n) operations and sorted keys.HashSet<T>
andBTreeSet<T>
: Store unique values.HashSet
uses hashing (O(1) average),BTreeSet
is tree-based (O(log n)) and sorted.VecDeque<T>
: A double-ended queue allowing efficient insertion/removal at both ends.LinkedList<T>
: A doubly linked list; efficient insertion/removal at known positions, but less cache-friendly thanVec
.
All these types are generic, just like Vec<T>
and HashMap<K, V>
.