class Solution { bool isSubtree(TreeNode* pRootA, TreeNode* pRootB) { if (pRootB == NULL) return true; if (pRootA == NULL) return false; if (pRootB->val == pRootA->val) { return isSubtree(pRootA->left, pRootB->left) && isSubtree(pRootA->right, pRootB->right); } else return false; } public: bool HasSubtree(TreeNode* pRootA, TreeNode* pRootB) { if (pRootA == NULL || pRootB == NULL) return false; return isSubtree(pRootA, pRootB) || HasSubtree(pRootA->left, pRootB) || HasSubtree(pRootA->right, pRootB); } };