LeetCode559.N叉树的最大深度

题目来源：

https://leetcode-cn.com/problems/maximum-depth-of-n-ary-tree/

题目描述：

代码如下：

/*
// Definition for a Node.
class Node {
    public int val;
    public List<Node> children;

    public Node() {}

    public Node(int _val,List<Node> _children) {
        val = _val;
        children = _children;
    }
};
*/
class Solution {
    public int maxDepth(Node root) {
        if (root == null ) { return 0;}
        int res = 1;
        for (Node node : root.children) {
            res = Math.max(res, maxDepth(node) + 1);
        }
        return res;
    }
}