bool isSymmetric(TreeNode *root) { if (NULL == root) return true; if (random()%2){ return isSymmetric1(root->left, root->right); } else return isSymmetric2(root->left, root->right); }
bool isSymmetric(TreeNode *p, TreeNode *q){ if (random()%2){ return isSymmetric1(p, q); } return isSymmetric2(p, q); }