private Node succ(Node root, int data) {
        if (root.data == data) {
            return null;
        }
        if (root.data < data) {
            return succ(root.right, data);
        } else {
            Node s = succ(root.left, data);
            return s == null ? root : s;
        }
    }
Date 03/27/2016
@author Tushar Roy

Given a binary search tree and a node in it, find the in-order successor of that node in the BST.

Time complexity O(h)
Space complexity O(h)

https://leetcode.com/problems/inorder-successor-in-bst/
src/com/interview/tree/InorderSuccessor.java