leetcode------Maximum Depth of Binary Tree

标题：	Maximum Depth of Binary Tree
通过率：	44.2%
难度：	简单

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

利用递归的思路，遍历分别遍历左右子树，每次判断左右子树哪个深，返回深的一方便是二叉树的深度，具体代码如下：

/**
 * 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) {
        int depth1=0;
        int depth2=0;
        if(root==null) return 0;
        //left
        depth1=maxDepth(root.left);
        depth2=maxDepth(root.right);
        if(depth1>depth2)
            return depth1+1;
            else
                return depth2+1;
    }
}