Compilare: user.cpp: In function ‘int main()’: user.cpp:97:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < Range[i].size(); j ++ ) ^ user.cpp:77:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "arb.out", "w", stdout ); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:47:47: 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); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:69:51: 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); ^