Compilare: user.cpp: In function ‘void make()’: user.cpp:248:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < old.size(); ++i) { ^ user.cpp:251:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p >= sol.size() or sol[p] != old[i]) ^ user.cpp:255:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol.size(); ++i) { ^ user.cpp:258:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p >= old.size() or old[p] != sol[i]) ^ user.cpp: In function ‘int main()’: user.cpp:289:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sol.size() * 2 != have) { ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:34:51: 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); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:12:47: 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); ^