288. Print all nodes at a distance of K in BT

Given the root of a binary tree, the value of a target node target, and an integer k. Return an array of the values of all nodes that have a distance k from the target node.

The answer can be returned in any order (N represents null).

Note: Although input shows target as a value, internally it refers to the TreeNode with that value.

Example 1:

Input : root = [3, 5, 1, 6, 2, 0, 8, N, N, 7, 4] , target = 5, k = 2

Output : [1, 4, 7]

Explanation : The nodes that are a distance 2 from the target node (with value 5) have values 7, 4, and 1.

Example 2:

Input : root = [3, 5, 1, 6, 2, 0, 8, N, N, 7, 4] , target = 5, k = 3

Output : [0, 8]

Explanation : The nodes that are a distance 3 from the target node (with value 5) have values 0, 8.

Now Your Turn!

Pick the correct output for the given input

Input : root =[1, 2, 3, 4, null, 5, 6], target = 6, k = 2

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Constraints:

  • 1 <= Number of Nodes <= 103
  • -104 <= Node.val <= 104
  • All the values Node.val are unique.
  • target is the value of one of the nodes in the tree
  • 0 <= k <= 103

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Fun Facts

0
/**
* Definition for a binary tree node.
* struct TreeNode {
* int data;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int val) : data(val) , left(nullptr) , right(nullptr) {}
* };
**/
 
class Solution {
public:
vector<int> distanceK(TreeNode* root, TreeNode* target, int k){
//your code goes here
}
};
Test Case

Input:

K
Root
Target
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