Maximum Depth of Binary Tree

Given a binary 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.

class Solution {
public:
    int maxDepth(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (!root){
            return 0;
        }
        if (!root->left && !root->right){
            return 1;    
        }
        return max(maxDepth(root->left),maxDepth(root->right)) + 1;
    }
};