(1) 先序遍历构造字符串(2) 确定一个数组下标根据字符串按序还原树结构 /* struct TreeNode { int val; struct TreeNode *left; struct TreeNode *right; TreeNode(int x) : val(x), left(NULL), right(NULL) { } }; */ class Solution { public: string s=""; void dfs(TreeNode* p){ if(p==NULL){ ...