/** * struct TreeNode { * int val; * struct TreeNode *left; * struct TreeNode *right; * }; */ class Solution { public: /** * * @param root TreeNode类 * @return int整型 */ int maxDepth(TreeNode* root) { if (root == nullptr) return 0; int l_deep = maxDepth(root->left); int r_deep = maxDepth(root->right); return max(l_deep, r_deep) + 1; } };