问题描述
代码
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
bool check(TreeNode *a,TreeNode *b) {判断两棵树是否对称
if(a==NULL&&b==NULL) return true;
if(a==NULL||b==NULL) return false;
if(a->val!=b->val) return false;
return (check(a->left,b->right)&&check(a->right,b->left));
}
public:
bool isSymmetric(TreeNode* root) {
return check(root,root);
}
};