感觉逐渐掌握了bool递归的写法(感觉)

C++ 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 {
public:
    bool isSymmetric(TreeNode* root) {
    //思路：深搜，一个左一个右，遇到不一样的就返回错
        return judge(root,root);
    }
    bool judge(TreeNode* subroot1,TreeNode* subroot2){
        if(!subroot1 && !subroot2) return true;
        if((!subroot1 && subroot2) ||(!subroot2 && subroot1)) return false;
        if(subroot1->val !=subroot2->val) return false;
        return judge(subroot1->left,subroot2->right)&&judge(subroot1->right,subroot2->left);
    }
};