void lyndon(string s) {

          int n = (int) s.length();

          int i = 0;

          while (i < n) {

                   int j = i + 1, k = i;

                   while (j < n && s[k] <= s[j]) {

                             if (s[k] < s[j]) k = i;

                             else ++k;

                             ++j;

                   }

                   while (i <= k) {

                             cout << s.substr(i, j - k) << ' ';

                             i += j - k;

                   }

          }

          cout << endl;

}