Compilare: user.cpp: In function ‘void Solve()’: user.cpp:106:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < L[i].size(); j++) ^ user.cpp: In member function ‘void InputReader::nxt()’: user.cpp:21:50: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, sizeof(char), BUFF_SIZE, fin); ^