Measure the Longest Root-to-Leaf Node Path
Company: Google
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Find the maximum depth of a binary tree. Depth counts nodes, so it is the greatest number of nodes on any path beginning at the root and ending at a leaf. An empty tree has depth 0.
```cpp
int maxDepth(TreeNode* root);
```
The supplied `TreeNode` contains `val`, `left`, and `right`. Brackets in examples describe its level-order structure, not an array parameter.
### Examples
```text
Input: root = [6,2,9,null,4,null,11,null,5]
Output: 4
```
The path through values 6,2,4,5 contains four nodes.
```text
Input: root = []
Output: 0
```
### Constraints
- There are between 0 and 10000 nodes.
- Each node value is between -100 and 100, inclusive.
Overview: Measure binary-tree maximum depth as the node count on its longest root-to-leaf path.
Community answers
Answer by Coderka14
class Solution
{
public:
int maxDepth(TreeNode* root)
{
if (root == nullptr)
{
return 0;
}
int leftDepth = maxDepth(root->left);
int rightDepth = maxDepth(root->right);
return 1 + max(leftDepth, rightDepth);
}
};