作者:牛客728711568号链接:https://www.nowcoder.com/discuss/375626499209109504来源:牛客网一道常见的二叉树层序遍历class Solution {public:vector<vector< int>> res;void ftraversal( vector< TreeNode*> temp){vector< int> floor;vector<TreeNode*> buf;for( auto ch:temp){if(!ch){floor. push_back( ch-> val);buf. push_back( ch-> left);buf. push_back( ch-> right);}}res. push_back(floor);ftraversal(buf);return ;}vector< vector< int>> levelOrder( TreeNode * root) {if(!root)return res;vector<TreeNode*> a;a. push_back(root);ftraversal(a);return res;}};为啥我的代码执行到 ftraversal (a);这里跳转的时候就会报错呢有没有大佬可以帮我看一下