Challenge 3: Finding Ancestors of a Given Node in a BST

Problem statement

Implement the string findAncestors(Node *rootNode, int k) function, which will find the ancestors of the node whose value is “k.”. Here rootNode is the root node of a binary search tree, and k is an integer value of the node whose ancestors you need to find. An illustration is also given below. Your code is evaluated on the tree given in the example.

Input

This is the root node and a number k.

Output

It returns all the ancestors of k in the binary search tree in a string separated by a comma.

Sample input

bst = {
    6 -> 4,9
    4 -> 2,5
    9 -> 8,12
    12 -> 10,14
}
where parent -> leftChild,rightChild

k = 10

Sample output

12,9,6,