C++速通LeetCode简单第11题-对称二叉树
递归法：
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
bool isSymmetric(TreeNode* root) {
return isMirror(root,root);
}
bool isMirror(TreeNode* t1,TreeNode* t2)
{
if(t1==nullptr&&t2==nullptr)
return true;
if(t1==nullptr||t2==nullptr)
return false;
return((t1->val==t2->val)&&isMirror(t1->right,t2->left)&&isMirror(t1->left,t2->right));
}
};