Recursive Search, Recursive Data Structure
		Recursive Array Search Recursive linear: O(n).  Average: n/2. Recursive binary: O(log n), because we cut the search set in half with every try.  Each doubling of the array size requires only one additional probe. What's a binary number divided by two, again and again and again? Recursive Data Structures A data structure that has another version of itself as a component: Tree, LinkedList. Linked List: Collection of nodes such that each node references another linked list. Add, size, replace: all can be accomplished with recursion. Backtracking Maze example XML Using recursion to put name:value pairs of XML file into a HashMap   Box Trace