Maximum Depth of Binary Tree:二叉树深度

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.

思路：标准的深度优先遍历，没什么可说的。

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */class Solution {    int max = 0;    public void dfs(TreeNode n,int depth)    {        if(n==null) return;        max = Math.max(max,depth);        dfs(n.left,depth+1);        dfs(n.right,depth+1);    }     public int maxDepth(TreeNode root) {        if(root == null) return 0;        dfs(root,1);        return max;    }}