Compilare: user.cpp: In function ‘int in_hash(int)’: user.cpp:50:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < V[y].size(); ++ i) ^ user.cpp: In function ‘int main()’: user.cpp:81:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("progr2.out", "w", stdout); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:16:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:43:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^