calculating depth of a binary tree in Python

Question

I am new to programming and am trying to calculate the depth of a binary tree in Python . I believe that my error is because depth is a method of the Node class and not a regula

Answer 1

You've got four cases to consider:

1. Both subtrees are empty.
2. The left subtree alone is empty.
3. The right subtree alone is empty.
4. Neither subtree is empty.

You've covered cases 1 and 4, but missed 2 and 3. The fix:

# Return height of tree rooted at this node.
def depth(self):
    if self.left == None and self.right == None:
        return 1
    elif self.left == None:
        return self.right.depth() + 1
    elif self.right == None:
        return self.left.depth() + 1
    else:
        return max(self.left.depth(), self.right.depth()) + 1