Compilare: user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:14:47: 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:44:51: 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 function ‘int main()’: user.cpp:172:46: warning: array subscript is below array bounds [-Warray-bounds] pairs[labels[a - 'a' + 1][b - 'a' + 1]].push_back(i); ^ user.cpp:172:33: warning: array subscript is below array bounds [-Warray-bounds] pairs[labels[a - 'a' + 1][b - 'a' + 1]].push_back(i); ^