鏈接：https://leetcode.com/submissions/detail/136407355/
難度：Easy
題目：104. 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.
翻譯：給定一棵二叉樹，找到它的最大深度。最大深度是沿著從根節(jié)點(diǎn)到最遠(yuǎn)葉節(jié)點(diǎn)的最長路徑的節(jié)點(diǎn)的數(shù)量扔亥。
思路：用深度優(yōu)先搜索DFS遞歸遍歷二叉樹是偷，搜索判斷左右子樹的深度孰大孰小即可内列，從根節(jié)點(diǎn)往下一層樹的深度即自增1孽锥，遇到NULL時(shí)即返回0咐汞。
參考代碼：
Java
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public int maxDepth(TreeNode root) {
if(root == null)
return 0;
return (1+Math.max(maxDepth(root.left), maxDepth(root.right)));
}
}
