101.对称二叉树

😂递归

class Solution {
public:
    bool isSymmetric(TreeNode* root) {
        if(!root)
            return true;
        return comp(root->left, root->right);
    }
    bool comp (TreeNode* l, TreeNode* r){
        if(!l && !r) {
            return true;
        }
        if(!l || !r) 
            return false;
        bool mb = l->val == r->val;
        bool lb = comp(l->left, r->right);
        bool rb = comp(l->right, r->left);
        return lb && rb && mb;
    }
};

Accepted

195/195 cases passed (8 ms)

Your runtime beats 64.49 % of cpp submissions

Your memory usage beats 5.1 % of cpp submissions (15.3 MB)