private static Node createNullLeafNode(Node parent) {
        Node leaf = new Node();
        leaf.color = Color.BLACK;
        leaf.isNullLeaf = true;
        leaf.parent = parent;
        return leaf;
    }
Date 10/29/2015
@author Tushar Roy

Red Black Tree

Time complexity
Insert - O(logn)
Delete - O(logn)
Search - O(logn)

Does not work for duplicates.

References
http://pages.cs.wisc.edu/~skrentny/cs367-common/readings/Red-Black-Trees/
https://en.wikipedia.org/wiki/Red%E2%80%93black_tree
src/com/interview/tree/RedBlackTree.java