What is the complexity of OrderedDictionary?

No one said that OrderedDictionary is having two copies of elements, one in a hashtable and other in 开发者_JAVA百科a list, I can't find complexity measurements at MSDN for OrderedList.

thanks

---

Have a look at

OrderedDictionary: A generic implementation of IOrderedDictionary

This implementation of an ordered dictionary is very good at lookup operations: the array allows O(1) lookups by index, and the hashtable allows O(1) lookups by key. However, the necessity of keeping the array synchronized with the hashtable means that insert/delete operations have the performance disadvantage of performing those operations on an array (O(n) at worst). There is also, of course, the extra memory requirement of storing both data structures. Because of these disadvantages, OrderedDictionary should only be used when insert/delete operations will be minimal and there is a need to efficiently access elements by index and/or key.