Question

I know that SortedDictionary is a binary search tree (and it can almost do what I need to do!) but I can’t figure out how to do everything I need in the correct complexity.

So here are the constraints (and the data structure which I know has it)

1. Inserting and Deletion in O(log n) (SortedDictionary)
2. Search in O(log n) (SortedDictionary & SortedList)
3. Iteration from one searched element to another in O(log n) + O(m) (where m is the number of elements in between) (SortedList)

As you can see, I don’t know how to get SortedDictionary to do number 3. Basically what I need to do is get all the elements with a range without iterating the set.

Please tell me if my question isn’t clear.

Answer 1

This seems to describe a B+ tree perfectly: http://en.wikipedia.org/wiki/B%2B_tree :

• Inserting a record requires O(log(n)) operations in the worst case
• Finding a record requires O(log(n)) operations in the worst case
• Performing a range query with k elements occurring within the range requires O(log(n) + k) operations in the worst case.

A C# implementation seems to exist here: http://bplusdotnet.sourceforge.net/