Lowest Common Ancestor of a Binary Tree - Recursive Solution

Question

This is a leetcode question: https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/

My code is here

class CommonAncestor:

    def traverse(self, root, A, B):

        if not root:
            return None

        return self.helper(root, A, B)

    def helper(self, node, A, B):
        print(node)
        if node:        

            left = self.helper(node.left, A, B)
            right = self.helper(node.right, A, B)

            if node.val == A or node.val == B:
                return node

            if left and right:
                return node
            elif left or right:
                return left or right
            else:
                return None

Can someone please explain why this code doesn't work? It runs perfectly on my VS code but its unable to pass the test case. I have created the exact same tree here:

class TreeNode:

    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None


obj = CommonAncestor()

root = TreeNode(3)

root.left = TreeNode(5)
root.left.left = TreeNode(6)
root.left.right = TreeNode(2)
root.left.right.left = TreeNode(7)
root.left.right.right = TreeNode(4)

root.right = TreeNode(1)
root.right.left = TreeNode(0)
root.right.right = TreeNode(8)
root.right.right.left = None
root.right.right.right = None

I can't figure out if this is leetcode specific or its my code... Thanks so much in advance!

Answer 1

Okay figured it out... LeetCode's input type was a TreeNode while my input type was a int...