python-random/max_depth_binary_tree.py at master · dev-hkim/python-random · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
class Solution:
    def maxDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if root is None:
            return 0
        else:
            left_height = self.maxDepth(root.left)
            right_height = self.maxDepth(root.right)
            return max(left_height, right_height) + 1

'''
       3
      / \
    9    20
         / \
        15  7

maxDepth(3):
  left_height = maxDepth(9) << 1
  right_height = maxDepth(20) << 2

  2+1

  --
maxDepth(20):
  left_height = 1
  right_height = 1
  max(1) + 2
--
maxDepth(15):
  left_height = 0
  right_height = 0

'''