Leetcode 559. Maximum Depth of N-ary Tree

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

    Node() {}

    Node(int _val, vector<Node*> _children) {
        val = _val;
        children = _children;
    }
};
*/
class Solution {
public:
    int maxDepth(Node* root) {
        if(!root) {
			return 0;
		}
		if(root->children.size() == 0) {
			return 1;
		}
		int max = 0;
		for(int i = 0; i < root->children.size(); i++) {
			int depth = maxDepth(root->children[i]);
			if(depth > max) {
				max = depth;
			}
		}
		return max + 1;
    }
};