/** struct TreeNode { int val; struct TreeNode *left; struct TreeNode *right; TreeNode(int x) : val(x), left(nullptr), right(nullptr) {} }; / class Solution { public: /* 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 @param root TreeNode类 @return int整型vector<vector<>> / vector<vector &...