Given the root node of a binary tree , a target node target , and an integer value K . Write a program to return a list of the values of all nodes that are at a distance K from the target node.

Problem Note

  • The answer can be returned in any order.
  • The given tree is non-empty.
  • Each node in the tree has unique values
  • The target node is a node in the tree.

Given the following binary tree: root = [5, 6, 3, 1, 7, 9, 4, null, null, 2, 0]

Example 1 

Input: root = [5, 6, 3, 1, 7, 9, 4, null, null, 2, 0], target = 6, K = 2
Output: [2, 0, 3]
Explanation: The nodes that are a distance 2 from the target node with value 6 have values 2, 0, and 3.