LeetCode - 104. Maximum Depth of Binary Tree(TreeNode, Recursion, DFS, BFS)*

문제

Given the of a binary tree, return its maximum depth.root
A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

https://leetcode.com/problems/maximum-depth-of-binary-tree/

Example 1:

Input: root = [3,9,20,null,null,15,7]
Output: 3

Example 2:

Input: root = [1,null,2]
Output: 2

풀이

class Solution {
    public int maxDepth(TreeNode root) {
        if(root==null) return 0;
        
        int left = maxDepth(root.left);
        int right = maxDepth(root.right);
        return Math.max(left,right)+1;   
    }
}