Compilare: main.cpp: In function 'int main()': main.cpp:29:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (query(s) == s.size()) cnt[i] += 1; ~~~~~~~~~^~~~~~~~~~~ main.cpp:29:35: warning: array subscript has type 'char' [-Wchar-subscripts] if (query(s) == s.size()) cnt[i] += 1; ^ main.cpp:35:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j <= ans.size(); ++j) { ~~^~~~~~~~~~~~~ main.cpp:37:16: warning: array subscript has type 'char' [-Wchar-subscripts] while (cnt[i] > 0) { ^ main.cpp:39:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (query(u.insert(j, c + 1, i)) == u.size() + c + 1) c += 1; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~ main.cpp:41:10: warning: array subscript has type 'char' [-Wchar-subscripts] cnt[i] -= 1; ^ main.cpp:22:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("password2.in", "r", stdin); ^ main.cpp:23:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("password2.out", "w", stdout); ^