class Solution { public: string oddString(vector<string>& words) { int n1=words.size(); int k = words[0].size(); map<vector<int>, int> m; vector<vector<int>> v; for(int i=0;i<n1;i++) { //int n2=words[i].length(); vector<int> a(k-1,0); //a[k-1]=i; for(int j=0;j<k-1;j++) { a[j]=words[i][j+1]-words[i][j]; } v.push_back(a); m[a]++; } vector<int>v2; string s; for(auto x:m) { if(x.second==1) { for(int i=0;i<x.first.size();i++) { v2.push_back(x.first[i]); } break; } } for(int i=0;i<n1;i++) { if(v[i]==v2) { s=words[i]; } } return s; } };