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.

问题：

　　求二叉树的最深深度。

/**
 * Definition for binary tree
 * 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;
        int leftdepth = maxDepth(root.left);
        int rightdepth = maxDepth(root.right);
        
        return Math.max(leftdepth,rightdepth)+1;
        
    }
}