bool isSymmetricalTree(struct TreeNode* pRoot, struct TreeNode* pRoot2) { if (pRoot == NULL && pRoot2 == NULL) return true; if (pRoot == NULL || pRoot2 == NULL) return false; if (pRoot->val == pRoot2->val) { if (isSymmetricalTree(pRoot->left, pRoot2->right) && isSymmetricalTree(pRoot2->left, pRoot->right)) return true; } return false; } bool isSymmetrical(struct TreeNode* pRoot ) { // write code here if (pRoot == NULL) return true; return isSymmetricalTree(pRoot->left, pRoot->right); }