Compilare: main.cpp: In function 'void go(int)': main.cpp:30:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < n && Hash.size() <= u) { ~~~~~~~~~~~~^~~~ main.cpp:32:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (Hash.size() >= l) { ~~~~~~~~~~~~^~~~ main.cpp: In function 'int main()': main.cpp:41:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.in", "r", stdin); ^ main.cpp:42:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.out", "w", stdout); ^