Compilare: user.cpp: In function ‘ll solve(int, reader&)’: user.cpp:87:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (l < v[i].size()) { ^ user.cpp:88:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (r < v[i + 1].size() - 1 && abs(v[i + 1][r + 1] - v[i][l]) < abs(v[i + 1][r] - v[i][l])) { ^ user.cpp: In member function ‘void reader::adv()’: user.cpp:43:34: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(b, S, 1, f); ^ user.cpp: In constructor ‘reader::reader(const char*)’: user.cpp:19:30: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(b, S, 1, f); ^