经典简单问题 problem link
note:
(1)递归要有结束条件
(2)此题可用DFS,BFS解题
code:
/**
* 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;
if(root.left==null && root.right==null)
return 1;
return 1+(int)Math.max(maxDepth(root.left),maxDepth(root.right));
}
}