K nearest Element in BST
Idea is to use a queue in inorder fashion which will make sure that the output is in sorted order
If queue size>=k which means we have to chek if first of the queue is not nearer to the current root element then poll from the queue and add current
void KnearestElement(Node root, int k, int x, Queue<Integer> q) {
if(root == null)
return ;
KnearestElement(root.left, k, x, q);
if(root.data !=x) {
if(q.size()<k)
q.add(root.data);
else if(Math.abs(q.peek()-x)>Math.abs(root.data-x)) {
q.poll();
q.add(root.data);
}}
KnearestElement(root.right, k, x, q);
}