[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:

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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:

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Input: root = [1]
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
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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