func_code_string: #include <bits/stdc++.h>   using namespace std;   void solve() {     string s;     cin >> s;     unordered_map<char, vector<long long int> > um;     long long int i;     for (i = 0; i < s.length(); i++) {       um[s[i]].push_back(i);     }     long long int last = -1;     bool flag;     string ans =   ;     for (i = 25; i >= 0; i--) {       char ch =  a  + i;       auto f = um.find(ch);       if (f != um.end()) {         for (auto it : um[ch]) {           if (it > last) {             ans += string(1, s[it]);             flag = true;           }         }         if (flag == true) last = um[ch][um[ch].size() - 1];       }       flag = false;     }     cout << ans << endl;   }   int main() {     solve();     return 0;   }   