leetcode:101.对称二叉树

借用二叉树是否相同的代码改动左右孩子相等对应关系，即为是否对称。

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     struct TreeNode *left;*     struct TreeNode *right;* };*/bool isSameTree(struct TreeNode* p, struct TreeNode* q){if(p==NULL&&q==NULL)return true;if(p==NULL || q == NULL)return false;if(p->val != q->val){return false;}return isSameTree(p->left,q->right)&&  //此处更改为对称isSameTree(p->right,q->left);
}
bool isSymmetric(struct TreeNode* root){if(root == NULL)return true;elsereturn isSameTree(root->left, root->right); 
}