leetcode:Minimum Depth of Binary Tree【Python版】

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

class Solution:
# @param root, a tree node
# @return an integer
def minDepth(self, root):
if root == None:
return 0
if root.left==None and root.right==None:
return 1
l,r = 9999,9999
if root.left!=None:
l = self.minDepth(root.left)
if root.right!=None:
r = self.minDepth(root.right)
if l<r:
return 1+l
return 1+r