Given a string, we can "shift" each of its letter to its successive letter, for example: "abc" -> "bcd". We can keep "shifting" which forms the sequence:

"abc" -> "bcd" -> ... -> "xyz"

Given a list of strings which contains only lowercase alphabets, group all strings that belong to the same shifting sequence.

For example, given: ["abc", "bcd", "acef", "xyz", "az", "ba", "a", "z"], 

A solution is:

[  ["abc","bcd","xyz"],  ["az","ba"],  ["acef"],  ["a","z"]]

 

class Solution {public:    vector
      
       
        > groupStrings(vector
        
         & strings) {         unordered_map
         
          
           >mp;         for(auto str:strings){             string t = shifted(str);             mp[t].push_back(str);         }         for(auto it = mp.begin();it!=mp.end();it++)             sort(it->second.begin(),it->second.end());         vector
           
            
             > res; for(auto it = mp.begin();it!=mp.end();it++) res.push_back(it->second); return res; }private: string shifted(string str) { string t; int diff=0; for(int i = 1;i