题目描述：
Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
解题思路：
分左子树和右子数递归调用。
代码如下：
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public int maxDepth(TreeNode root) {
if(root == null)
return 0;
else
return Math.max(maxDepth(root.left) + 1, maxDepth(root.right) + 1);
}
}
Java [Leetcode 104]Maximum Depth of Binary Tree
原文：http://www.cnblogs.com/zihaowang/p/5065658.html