Java中的数据结构是否与TreeSet类似但允许重复？

Question

I want to keep the ordering and allow duplicates. Should I build one for myself? Or is there some way that I can tweak Comparator (which I think remove() and insert() are using the same)? Thanks.

I want remove() to be in O(log n) and add() to be O(log n) as well.

PriorityQueue is one way but its remove() method takes O(n). If possible, how could I tweak this?

Answer 1

Can you see TreeBag of Apache Commons-Collections ? This use a TreeMap to provide the data storage, which provides provides guaranteed log(n) time cost for the containsKey , get , put and remove operations.

A Bag stores each object in the collection together with a count of occurrences.

Answer 2

Guava's TreeMultiset , perhaps? Unlike Apache Commons, TreeMultiset and the other Multiset s get along with generics and properly obey the Collection contract, which makes it somewhat friendlier to use.

(Disclosure: I contribute to Guava.)