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