How to find the closest element to a given key value in a binary search tree?

Question

Given a bst with integer values as keys how do I find the closest node to that key in a bst ? The BST is represented using a object of nodes (Java). Closest will be for eg 4

Answer 1

The problem with the approach "left right traversal and finding the closest" is that it depends over the sequence in which elements were entered to create BST. If we search 11 for the BST sequence 22, 15, 16, 6,14,3,1,90, the above method will return 15 while the correct answer is 14. The only method should be using recursion to traverse all the nodes, returning the closest one as the result of the recursive function. This'll give us the closest value