【关关的刷题日记57】Leetcode 101. Symmetric Tree

class Solution {public:
    bool dfs(TreeNode* root1, TreeNode* root2)
    {
        if(!root1 && !root2)
            return true;
        if(!root2 || !root1 || root1->val!=root2->val)
            return false;
        return dfs(root1->left, root2->right) && dfs(root1->right, root2->left);
    }

    bool isSymmetric(TreeNode* root) {
        if(!root)
            return true;
        else
            return dfs(root->left, root->right);}};