``````Given a n-ary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value (See examples).

Example 1:

Input: root = [1,null,3,2,4,null,5,6]
Output: 3
Example 2:

Input: root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14]
Output: 5

Constraints:

The depth of the n-ary tree is less than or equal to 1000.
The total number of nodes is between [0, 10^4].
``````

``````class Solution {
public:
static int dfs(Node *root, int cur_level) {
if (root->children.empty()) {
return cur_level;
}

int level = 0;
for (auto v : root->children) {
int child_level = dfs(v, cur_level + 1);
if (child_level > level) {
level = child_level;
}
}
return level;
}

static int Main(Node* root) {
if (nullptr == root) {
return 0;
}
return dfs(root, 1);
}
};
`````` ### 作者 