leetcode--Maximum Depth of Binary Tree

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：使用递归思路，求最大的左子树和最大的右子树的最大。
java版：

public class Solution {    public int maxDepth(TreeNode root) {        if(root==null) return 0;        else         return Math.max(maxDepth(root.left),maxDepth(root.right))+1;    }}

c++版：

class Solution {public:    int maxDepth(TreeNode* root) {    if(root==NULL)    return 0;    else        return max(maxDepth(root->left),maxDepth(root->right))+1;    }};