Suppose we will need these operations (and only these) on data to be stored and all operations must have the indicated running time restriction:

1. insert(x) - must be O(log(N), preferably O(1)
2. contains(x) - must be O(1)

A class is to be written with these public methods. A private data member will store the actual data and be used to implement the public methods.

Which type could be used for the private data member?

• LinkedList
• ArrayList
• Binary Search Tree
• AVL Tree
• Min Heap
• Max Heap