Measure the Maximum Root-to-Leaf Depth of an N-ary Tree
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Given Node* root, return the greatest number of nodes on a root-to-leaf path. An empty tree has depth zero. Node exposes val and vector<Node*> children; retain this native node interface. In displayed level-order examples, null separates each parent's children group.
```cpp
class Solution {
public:
int maxDepth(Node* root);
};
```
### Examples
**Example 1:**
```text
root = [8,null,2,5,null,9]
Output: 3
Explanation: Root 8 has children 2 and 5; node 2 has child 9.
```
**Example 2:**
```text
root = []
Output: 0
Explanation: There is no root.
```
### Constraints
- The N-ary tree has 0..10000 nodes. Its depth does not exceed 1000.
### Clarifying Questions
Count nodes along the path and preserve the Node.children interface and empty-tree case.
```hint Read the boundary condition
How should a child's depth relate to its parent's depth?
```
### Contract considerations
Count nodes along the path and preserve the Node.children interface and empty-tree case.
