/* struct TreeNode { int val; struct TreeNode *left; struct TreeNode *right; TreeNode(int x) : val(x), left(NULL), right(NULL) { } };*/ class Solution { public: int TreeDepth(TreeNode* pRoot) { if (pRoot == nullptr) return 0; return 1 + std::max(TreeDepth(pRoot->left), TreeDepth(pRoot->right)); } };