222.md

compare the depth between left sub tree and right sub tree. A, If it is equal, it means the left sub tree is a full binary tree B, It it is not , it means the right sub tree is a full binary tree

• 80ms
• 69%

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def countNodes(self, root: TreeNode) -> int:
        if not root:
            return 0
        left = self.getDepth(root.left)
        right = self.getDepth(root.right)
        if left==right:
            return 2**(left) + self.countNodes(root.right)
        else:
            return 2**(right) + self.countNodes(root.left)
        
    def getDepth(self, root):
        if not root: return 0
        return 1+self.getDepth(root.left)