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.

 

/**

 * Definition for binary tree

 * struct TreeNode {

 *     int val;

 *     TreeNode *left;

 *     TreeNode *right;

 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}

 * };

 */

class Solution {

public:

    int maxDepth(TreeNode *root) {

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

        if(!root) return 0;

        

        int l = maxDepth(root -> left);

        int r = maxDepth(root -> right);

        

        return max(l, r) + 1;

    }

};