Java Set

name add contains next comment HashSet o(1) o(1) o(h/n) based on hashmap, using key to store object LinkedHashSet o(1) o(1) o(1) based on linkedhashmap, using key to store object. double-linked entry to get constant-time complexity when call next on iteration EnumSet o(1) o(1) o(1) using bit vector internally to represent enum elements; a variable of long represents all enum elements if enum’s length < 64. otherwise use long[] to represent enum TreeSet o(log(n)) o(log(n)) o(log(n)) TreeMap underlying CopyOnWriteArraySet o(n) o(n) o(1) CopyOnWriteArrayList underlying ConcurrentSkipListSet o(log(n)) o(log(n)) o(1) concurrentSkipListMap underlying