原题地址：http://oj.leetcode.com/problems/minimum-depth-of-binary-tree/
题意：
Given a binary tree, find its minimum depth.
The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.
解题思路：分几种情况考虑：1，树为空，则为0。 2，根节点如果只存在左子树或者只存在右子树，则返回值应为左子树或者右子树的（最小深度+1）。 3，如果根节点的左子树和右子树都存在，则返回值为（左右子树的最小深度的较小值+1）。
代码：
# 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 self.minDepth( root.right ) + 1 if root.left != None and root.right == None: return self.minDepth( root.left ) + 1 return min( self.minDepth( root.left ), self.minDepth( root.right ) ) + 1
[leetcode]Minimum Depth of Binary Tree @ Python,布布扣,bubuko.com