Maximum Depth of Binary Tree

Maximum Depth of Binary Tree

/**
 * struct TreeNode {
 *    int val;
 *    TreeNode *left;
 *    TreeNode *right;
 *    TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode* root) {
        if(!root) return 0;
        int leftMax = maxDepth(root->left);
        int rightMax = maxDepth(root->right);
        return 1 + max(leftMax, rightMax);
    }
};