python寫算法題：leetcode: 111. Minimum Depth of Binary Tree

class Solution(object):
    def deep(self, node, level):
        if node==None: return level
        if node.left==None:
            return self.deep(node.right,level+1)
        if node.right==None: 
            return self.deep(node.left,level+1)
        return min(self.deep(node.left,level+1), self.deep(node.right,level+1))
    def minDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if root==None: return 0
        return self.deep(root, 0)