563. Binary Tree Tilt - LeetCode Solution

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def findTilt(self, root: Optional[TreeNode]) -> int:
        def trav(root):
            if not root:
                return [0,0]
            a = trav(root.left)
            b = trav(root.right)
            
            return [abs(a[1] - b[1]) + a[0] + b[0] , a[1]+b[1]+ root.val]
        
        a = trav(root)
        print(a)
        return a[0]