leetcode:Minimum Depth of Binary Tree【Python版】

1、类中递归调用添加self；

2、root为None，返回0

3、root不为None，root左右孩子为None，返回1

4、返回l和r最小深度，l和r初始为极大值；

 # 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