559. Maximum Depth of N-ary Tree

 1 /*
 2 // Definition for a Node.
 3 class Node {
 4 public:
 5     int val;
 6     vector<Node*> children;
 7 
 8     Node() {}
 9 
10     Node(int _val, vector<Node*> _children) {
11         val = _val;
12         children = _children;
13     }
14 };
15 */
16 class Solution {
17 public:
18     int maxDepth(Node* root) {
19         int depth = 0;
20         dfs(root, depth);
21         return max;
22     }
23     void dfs(Node* root, int& depth) {
24         if (root == NULL) 
25             return;
26         depth += 1;
27         for (auto child : root->children) {
28             dfs(child, depth);
29             depth -= 1;
30         }
31         if (root->children.size() == 0) {
32             if (depth > max) {
33                 max = depth;
34             }
35         }
36     }
37     int max = 0;
38 };