#include <bits/stdc++.h> using namespace std; int query(string s); string guess(int n, int s){ string tmp = ""; vector<int> val(s,0), vec; for(int i = 0; i < s; i++){ while(true){ tmp += char(i+'a'); if((int)tmp.size() != query(tmp)) break; if((int) tmp.size()==n) return tmp; } val[i] = tmp.size()-1; if(val[i]) vec.push_back(i); tmp = ""; } sort(vec.begin(),vec.end(),[&](const int &a, const int &b)->bool{ return val[a] < val[b]; }); for(auto i : vec){ int m = tmp.size(); for(int j = 0; j < m;){ while(true){ tmp.insert(tmp.begin()+j,char(i+'a')); j++; m++; if(m!=query(tmp)) break; if(m==n) return tmp; } j--,m--; tmp.erase(tmp.begin()+j); j++; } while(true){ tmp += char(i+'a'); m++; if(m!=query(tmp)) break; if(m==n) return tmp; } m--; tmp.pop_back(); } return tmp; }