【leetcode】104. Maximum Depth of Binary Tree

题目要求：

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.

即给定一个二叉树，求它的最大深度

思路：递归求左子树和右子树的深度，然后返回较大者

/**
 * 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;
        }
        int left = maxDepth(root.left);
        int right = maxDepth(root.right);
        return (left>right?left:right)+1;
    }
}