Sum of Nodes with Even-Valued Grandparent
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.
Example 1
6
/ \
7 8
/ \ / \
2 7 1 3
/ / \ \
9 1 4 5Input
root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]Output
18The nodes with even-valued grandparents have values 9, 1, 4, and 5, which sum to 18.
Example 2
1
Input
root = [1]Output
0The single root node has no grandparent, so the sum is 0.
Constraints
- The number of nodes in the tree is in the range
[1, 10^4]. 1 <= Node.val <= 100