leetcode-python-二叉树的最小深度

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def minDepth(self, root: TreeNode) -> int:
        if not root:
            return 0 
        if root.left and root.right:
            return 1 + min(self.minDepth(root.left),self.minDepth(root.right))
        elif root.left:
            return 1 + self.minDepth(root.left)
        elif root.right:
            return 1 + self.minDepth(root.right)
        else:
            return 1