human
I am working on the file "03_BinaryTree_DivideConquer.ipynb".
The first task is:
Lowest Common Ancestor
Given the root and two nodes in a Binary Tree. Find the lowest common ancestor(LCA) of the two nodes.
The lowest common ancestor is the node with largest depth which is the ancestor of both nodes.
https://www.lintcode.com/en/problem/lowest-common-ancestor/
Example
For the following binary tree:
4
 / \
3   7
   / \
  5   6
LCA(3, 5) = 4
LCA(5, 6) = 7
LCA(6, 7) = 7
Can you write Python program for it?

Write me a Python program to find the lowest common ancestor(LCA) of the two nodes?
assistant
#Here is Python program to find the lowest common ancestor(LCA) of the two nodes.

"""
Definition of TreeNode:
class TreeNode:
    def __init__(self, val):
        self.val = val
        self.left, self.right = None, None
"""
import copy
class Solution:
    """
    @param root: The root of the binary search tree.
    @param A and B: two nodes in a Binary.
    @return: Return the least common ancestor(LCA) of the two nodes.
    """ 
    def lowestCommonAncestor(self, root, A, B):
        # write your code here
        if not root or root == A or root == B:
            return root
        
        left = self.lowestCommonAncestor(root.left, A, B)
        right = self.lowestCommonAncestor(root.right, A, B)
        
        if left and right:
            return root
        if left:
            return left
        if right:
            return right
        return None