# [Solved] Given the root of a binary tree, return the sum of values of nodes with an even-valued grandparent. If there are no nodes with an even-valued grandparent, return 0. A grandparent of a node is the parent of its parent if it exists.

## Question

Given the `root` of a binary tree, return the sum of values of nodes with an even-valued grandparent. If there are no nodes with an even-valued grandparent, return `0`.

grandparent of a node is the parent of its parent if it exists.

Example 1:

```Input: root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]
Output: 18
Explanation: The red nodes are the nodes with even-value grandparent while the blue nodes are the even-value grandparents.
```

Example 2:

```Input: root = 
Output: 0
```

Constraints:

• The number of nodes in the tree is in the range `[1, 104]`.
• `1 <= Node.val <= 100`

## Python Solution

```def traverse(root,p,gp):
global ans
if root==None:return
if gp and gp.val%2==0:
ans+=root.val
traverse(root.left,root,p)
traverse(root.right,root,p)

class Solution:
def sumEvenGrandparent(self, root: TreeNode) -> int:
global ans
ans = 0
traverse(root,None,None)
return ans``` ##### Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

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