class Solution { private: const string letterMap[10] = { "", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz", }; 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 num string字符串 * @return string字符串vector */ vector<string> result; string s; void backtracking(const stri...
