题目

解题思路

递归

解题代码

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